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2020-02-06Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no ↵Daniel Thompson1-13/+15
regs" This reverts commit bbfceba15f8d1260c328a254efc2b3f2deae4904. When DBG_MAX_REG_NUM is zero then a number of symbols are conditionally defined. It is therefore not possible to check it using C expressions. Reported-by: Anatoly Pugachev <matorola@gmail.com> Acked-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: Use for_each_console() helperAndy Shevchenko1-6/+3
Replace open coded single-linked list iteration loop with for_each_console() helper in use. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: remove redundant assignment to pointer bpColin Ian King1-1/+0
The point bp is assigned a value that is never read, it is being re-assigned later to bp = &kdb_breakpoints[lowbp] in a for-loop. Remove the redundant assignment. Addresses-Coverity ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/20191128130753.181246-1-colin.king@canonical.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: Get rid of confusing diag msg from "rd" if current task has no regsDouglas Anderson1-15/+13
If you switch to a sleeping task with the "pid" command and then type "rd", kdb tells you this: No current kdb registers. You may need to select another task diag: -17: Invalid register name The first message makes sense, but not the second. Fix it by just returning 0 after commands accessing the current registers finish if we've already printed the "No current kdb registers" error. While fixing kdb_rd(), change the function to use "if" rather than "ifdef". It cleans the function up a bit and any modern compiler will have no trouble handling still producing good code. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191109111624.5.I121f4c6f0c19266200bf6ef003de78841e5bfc3d@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: Gid rid of implicit setting of the current task / regsDouglas Anderson3-9/+2
Some (but not all?) of the kdb backtrace paths would cause the kdb_current_task and kdb_current_regs to remain changed. As discussed in a review of a previous patch [1], this doesn't seem intuitive, so let's fix that. ...but, it turns out that there's actually no longer any reason to set the current task / current regs while backtracing anymore anyway. As of commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master") if we're backtracing on a task running on a CPU we ask that CPU to do the backtrace itself. Linux can do that without anything fancy. If we're doing backtrace on a sleeping task we can also do that fine without updating globals. So this patch mostly just turns into deleting a bunch of code. [1] https://lore.kernel.org/r/20191010150735.dhrj3pbjgmjrdpwr@holly.lan Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191109111624.4.Ibc3d982bbeb9e46872d43973ba808cd4c79537c7@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: kdb_current_task shouldn't be exportedDouglas Anderson1-1/+0
The kdb_current_task variable has been declared in "kernel/debug/kdb/kdb_private.h" since 2010 when kdb was added to the mainline kernel. This is not a public header. There should be no reason that kdb_current_task should be exported and there are no in-kernel users that need it. Remove the export. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191109111623.3.I14b22b5eb15ca8f3812ab33e96621231304dc1f7@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-01-31kdb: kdb_current_regs should be privateDouglas Anderson1-0/+1
As of the patch ("MIPS: kdb: Remove old workaround for backtracing on other CPUs") there is no reason for kdb_current_regs to be in the public "kdb.h". Let's move it next to kdb_current_task. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191109111623.2.Iadbfb484e90b557cc4b5ac9890bfca732cd99d77@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-10-28kdb: Tweak escape handling for vi usersDaniel Thompson1-2/+2
Currently if sequences such as "\ehelp\r" are delivered to the console then the h gets eaten by the escape handling code. Since pressing escape becomes something of a nervous twitch for vi users (and that escape doesn't have much effect at a shell prompt) it is more helpful to emit the 'h' than the '\e'. We don't simply choose to emit the final character for all escape sequences since that will do odd things for unsupported escape sequences (in other words we retain the existing behaviour once we see '\e['). Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191025073328.643-6-daniel.thompson@linaro.org
2019-10-28kdb: Improve handling of characters from different input sourcesDaniel Thompson1-19/+19
Currently if an escape timer is interrupted by a character from a different input source then the new character is discarded and the function returns '\e' (which will be discarded by the level above). It is hard to see why this would ever be the desired behaviour. Fix this to return the new character rather than the '\e'. This is a bigger refactor than might be expected because the new character needs to go through escape sequence detection. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191025073328.643-5-daniel.thompson@linaro.org
2019-10-28kdb: Remove special case logic from kdb_read()Daniel Thompson3-42/+42
kdb_read() contains special case logic to force it exit after reading a single character. We can remove all the special case logic by directly calling the function to read a single character instead. This also allows us to tidy up the function prototype which, because it now matches getchar(), we can also rename in order to make its role clearer. This does involve some extra code to handle btaprompt properly but we don't mind the new lines of code here because the old code had some interesting problems (bad newline handling, treating unexpected characters like <cr>). Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191025073328.643-4-daniel.thompson@linaro.org
2019-10-28kdb: Simplify code to fetch characters from consoleDaniel Thompson1-24/+14
Currently kdb_read_get_key() contains complex control flow that, on close inspection, turns out to be unnecessary. In particular: 1. It is impossible to enter the branch conditioned on (escape_delay == 1) except when the loop enters with (escape_delay == 2) allowing us to combine the branches. 2. Most of the code conditioned on (escape_delay == 2) simply modifies local data and then breaks out of the loop causing the function to return escape_data[0]. 3. Based on #2 there is not actually any need to ever explicitly set escape_delay to 2 because we it is much simpler to directly return escape_data[0] instead. 4. escape_data[0] is, for all but one exit path, known to be '\e'. Simplify the code based on these observations. There is a subtle (and harmless) change of behaviour resulting from this simplification: instead of letting the escape timeout after ~1998 milliseconds we now timeout after ~2000 milliseconds Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191025073328.643-3-daniel.thompson@linaro.org
2019-10-28kdb: Tidy up code to handle escape sequencesDaniel Thompson1-61/+67
kdb_read_get_key() has extremely complex break/continue control flow managed by state variables and is very hard to review or modify. In particular the way the escape sequence handling interacts with the general control flow is hard to follow. Separate out the escape key handling, without changing the control flow. This makes the main body of the code easier to review. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20191025073328.643-2-daniel.thompson@linaro.org
2019-10-24kdb: Avoid array subscript warnings on non-SMP buildsDaniel Thompson1-1/+1
Recent versions of gcc (reported on gcc-7.4) issue array subscript warnings for builds where SMP is not enabled. kernel/debug/debug_core.c: In function 'kdb_dump_stack_on_cpu': kernel/debug/debug_core.c:452:17: warning: array subscript is outside array +bounds [-Warray-bounds] if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) { ~~~~~~~~~^~~~~ kernel/debug/debug_core.c:469:33: warning: array subscript is outside array +bounds [-Warray-bounds] kgdb_info[cpu].exception_state |= DCPU_WANT_BT; kernel/debug/debug_core.c:470:18: warning: array subscript is outside array +bounds [-Warray-bounds] while (kgdb_info[cpu].exception_state & DCPU_WANT_BT) There is no bug here but there is scope to improve the code generation for non-SMP systems (whilst also silencing the warning). Reported-by: kbuild test robot <lkp@intel.com> Fixes: 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master") Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20191021101057.23861-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org>
2019-10-10kdb: Fix stack crawling on 'running' CPUs that aren't the masterDouglas Anderson3-12/+43
In kdb when you do 'btc' (back trace on CPU) it doesn't necessarily give you the right info. Specifically on many architectures (including arm64, where I tested) you can't dump the stack of a "running" process that isn't the process running on the current CPU. This can be seen by this: echo SOFTLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT # wait 2 seconds <sysrq>g Here's what I see now on rk3399-gru-kevin. I see the stack crawl for the CPU that handled the sysrq but everything else just shows me stuck in __switch_to() which is bogus: ====== [0]kdb> btc btc: cpu status: Currently on cpu 0 Available cpus: 0, 1-3(I), 4, 5(I) Stack traceback for pid 0 0xffffff801101a9c0 0 0 1 0 R 0xffffff801101b3b0 *swapper/0 Call trace: dump_backtrace+0x0/0x138 ... kgdb_compiled_brk_fn+0x34/0x44 ... sysrq_handle_dbg+0x34/0x5c Stack traceback for pid 0 0xffffffc0f175a040 0 0 1 1 I 0xffffffc0f175aa30 swapper/1 Call trace: __switch_to+0x1e4/0x240 0xffffffc0f65616c0 Stack traceback for pid 0 0xffffffc0f175d040 0 0 1 2 I 0xffffffc0f175da30 swapper/2 Call trace: __switch_to+0x1e4/0x240 0xffffffc0f65806c0 Stack traceback for pid 0 0xffffffc0f175b040 0 0 1 3 I 0xffffffc0f175ba30 swapper/3 Call trace: __switch_to+0x1e4/0x240 0xffffffc0f659f6c0 Stack traceback for pid 1474 0xffffffc0dde8b040 1474 727 1 4 R 0xffffffc0dde8ba30 bash Call trace: __switch_to+0x1e4/0x240 __schedule+0x464/0x618 0xffffffc0dde8b040 Stack traceback for pid 0 0xffffffc0f17b0040 0 0 1 5 I 0xffffffc0f17b0a30 swapper/5 Call trace: __switch_to+0x1e4/0x240 0xffffffc0f65dd6c0 === The problem is that 'btc' eventually boils down to show_stack(task_struct, NULL); ...and show_stack() doesn't work for "running" CPUs because their registers haven't been stashed. On x86 things might work better (I haven't tested) because kdb has a special case for x86 in kdb_show_stack() where it passes the stack pointer to show_stack(). This wouldn't work on arm64 where the stack crawling function seems needs the "fp" and "pc", not the "sp" which is presumably why arm64's show_stack() function totally ignores the "sp" parameter. NOTE: we _can_ get a good stack dump for all the cpus if we manually switch each one to the kdb master and do a back trace. AKA: cpu 4 bt ...will give the expected trace. That's because now arm64's dump_backtrace will now see that "tsk == current" and go through a different path. In this patch I fix the problems by catching a request to stack crawl a task that's running on a CPU and then I ask that CPU to do the stack crawl. NOTE: this will (presumably) change what stack crawls are printed for x86 machines. Now kdb functions will show up in the stack crawl. Presumably this is OK but if it's not we can go back and add a special case for x86 again. Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-10-10kdb: Fix "btc <cpu>" crash if the CPU didn't round upDouglas Anderson1-27/+34
I noticed that when I did "btc <cpu>" and the CPU I passed in hadn't rounded up that I'd crash. I was going to copy the same fix from commit 162bc7f5afd7 ("kdb: Don't back trace on a cpu that didn't round up") into the "not all the CPUs" case, but decided it'd be better to clean things up a little bit. This consolidates the two code paths. It is _slightly_ wasteful in in that the checks for "cpu" being too small or being offline isn't really needed when we're iterating over all online CPUs, but that really shouldn't hurt. Better to have the same code path. While at it, eliminate at least one slightly ugly (and totally needless) recursive use of kdb_parse(). Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-10-10kdb: Remove unused "argcount" param from kdb_bt1(); make btaprompt boolDouglas Anderson1-8/+6
The kdb_bt1() had a mysterious "argcount" parameter passed in (always the number 5, by the way) and never used. Presumably this is just old cruft. Remove it. While at it, upgrade the btaprompt parameter to a full fledged bool instead of an int. Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-10-10kgdb: Remove unused DCPU_SSTEP definitionDouglas Anderson1-1/+0
From doing a 'git log --patch kernel/debug', it looks as if DCPU_SSTEP has never been used. Presumably it used to be used back when kgdb was out of tree and nobody thought to delete the definition when the usage went away. Delete. Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-09-25kgdb: don't use a notifier to enter kgdb at panic; call directlyDouglas Anderson1-20/+11
Right now kgdb/kdb hooks up to debug panics by registering for the panic notifier. This works OK except that it means that kgdb/kdb gets called _after_ the CPUs in the system are taken offline. That means that if anything important was happening on those CPUs (like something that might have contributed to the panic) you can't debug them. Specifically I ran into a case where I got a panic because a task was "blocked for more than 120 seconds" which was detected on CPU 2. I nicely got shown stack traces in the kernel log for all CPUs including CPU 0, which was running 'PID: 111 Comm: kworker/0:1H' and was in the middle of __mmc_switch(). I then ended up at the kdb prompt where switched over to kgdb to try to look at local variables of the process on CPU 0. I found that I couldn't. Digging more, I found that I had no info on any tasks running on CPUs other than CPU 2 and that asking kdb for help showed me "Error: no saved data for this cpu". This was because all the CPUs were offline. Let's move the entry of kdb/kgdb to a direct call from panic() and stop using the generic notifier. Putting a direct call in allows us to order things more properly and it also doesn't seem like we're breaking any abstractions by calling into the debugger from the panic function. Daniel said: : This patch changes the way kdump and kgdb interact with each other. : However it would seem rather odd to have both tools simultaneously armed : and, even if they were, the user still has the option to use panic_timeout : to force a kdump to happen. Thus I think the change of order is : acceptable. Link: http://lkml.kernel.org/r/20190703170354.217312-1-dianders@chromium.org Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Kees Cook <keescook@chromium.org> Cc: Borislav Petkov <bp@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Feng Tang <feng.tang@intel.com> Cc: YueHaibing <yuehaibing@huawei.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-03kgdb: fix comment regarding static functionNadav Amit1-4/+1
The comment that says that module_event() is not static is clearly wrong. Signed-off-by: Nadav Amit <namit@vmware.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-09-03kdb: Replace strncmp with str_has_prefixChuhong Yuan1-1/+1
strncmp(str, const, len) is error-prone. We had better use newly introduced str_has_prefix() instead of it. Signed-off-by: Chuhong Yuan <hslester96@gmail.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner1-0/+1
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14kdb: Fix bound check compiler warningWenlin Kang1-1/+1
The strncpy() function may leave the destination string buffer unterminated, better use strscpy() instead. This fixes the following warning with gcc 8.2: kernel/debug/kdb/kdb_io.c: In function 'kdb_getstr': kernel/debug/kdb/kdb_io.c:449:3: warning: 'strncpy' specified bound 256 equals destination size [-Wstringop-truncation] strncpy(kdb_prompt_str, prompt, CMD_BUFLEN); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-12kdb: do a sanity check on the cpu in kdb_per_cpu()Dan Carpenter1-1/+1
The "whichcpu" comes from argv[3]. The cpu_online() macro looks up the cpu in a bitmap of online cpus, but if the value is too high then it could read beyond the end of the bitmap and possibly Oops. Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-12kdb: Get rid of broken attempt to print CCVERSION in kdb summaryDouglas Anderson2-2/+0
If you drop into kdb and type "summary", it prints out a line that says this: ccversion CCVERSION ...and I don't mean that it actually prints out the version of the C compiler. It literally prints out the string "CCVERSION". The version of the C Compiler is already printed at boot up and it doesn't seem useful to replicate this in kdb. Let's just delete it. We can also delete the bit of the Makefile that called the C compiler in an attempt to pass this into kdb. This will remove one extra call to the C compiler at Makefile parse time and (very slightly) speed up builds. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-02kdb: kdb_support: replace strcpy() by strscpy()Gustavo A. R. Silva1-1/+1
The strcpy() function is being deprecated. Replace it by the safer strscpy() and fix the following Coverity warning: "You might overrun the 129-character fixed-size string ks_namebuf by copying name without checking the length." Addresses-Coverity-ID: 138995 ("Copy into fixed size buffer") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-02gdbstub: Replace strcpy() by strscpy()Gustavo A. R. Silva1-2/+2
The strcpy() function is being deprecated. Replace it by the safer strscpy() and fix the following Coverity warning: "You might overrun the 1024-character fixed-size string remcom_in_buffer by copying cmd without checking the length." Addresses-Coverity-ID: 138999 ("Copy into fixed size buffer") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2019-05-02gdbstub: mark expected switch fall-throughsGustavo A. R. Silva1-2/+3
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warnings: kernel/debug/gdbstub.c: In function ‘gdb_serial_stub’: kernel/debug/gdbstub.c:1031:7: warning: this statement may fall through [-Wimplicit-fallthrough=] if (remcom_in_buffer[1] == '\0') { ^ kernel/debug/gdbstub.c:1036:3: note: here case 'C': /* Exception passing */ ^~~~ kernel/debug/gdbstub.c:1040:7: warning: this statement may fall through [-Wimplicit-fallthrough=] if (tmp == 0) ^ kernel/debug/gdbstub.c:1043:3: note: here case 'c': /* Continue packet */ ^~~~ kernel/debug/gdbstub.c:1050:4: warning: this statement may fall through [-Wimplicit-fallthrough=] dbg_activate_sw_breakpoints(); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/debug/gdbstub.c:1052:3: note: here default: ^~~~~~~ Warning level 3 was used: -Wimplicit-fallthrough=3 Notice that, in this particular case, the code comment is modified in accordance with what GCC is expecting to find. This patch is part of the ongoing efforts to enable -Wimplicit-fallthrough. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-12-30kdb: use bool for binary state indicatorsNicholas Mc Guire1-7/+7
defcmd_in_progress is the state trace for command group processing - within a command group or not - usable is an indicator if a command set is valid (allocated/non-empty) - so use a bool for those binary indication here. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-12-30kdb: Don't back trace on a cpu that didn't round upDouglas Anderson3-8/+14
If you have a CPU that fails to round up and then run 'btc' you'll end up crashing in kdb becaue we dereferenced NULL. Let's add a check. It's wise to also set the task to NULL when leaving the debugger so that if we fail to round up on a later entry into the debugger we won't backtrace a stale task. Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-12-30kgdb: Don't round up a CPU that failed rounding up beforeDouglas Anderson2-1/+20
If we're using the default implementation of kgdb_roundup_cpus() that uses smp_call_function_single_async() we can end up hanging kgdb_roundup_cpus() if we try to round up a CPU that failed to round up before. Specifically smp_call_function_single_async() will try to wait on the csd lock for the CPU that we're trying to round up. If the previous round up never finished then that lock could still be held and we'll just sit there hanging. There's not a lot of use trying to round up a CPU that failed to round up before. Let's keep a flag that indicates whether the CPU started but didn't finish to round up before. If we see that flag set then we'll skip the next round up. In general we have a few goals here: - We never want to end up calling smp_call_function_single_async() when the csd is still locked. This is accomplished because flush_smp_call_function_queue() unlocks the csd _before_ invoking the callback. That means that when kgdb_nmicallback() runs we know for sure the the csd is no longer locked. Thus when we set "rounding_up = false" we know for sure that the csd is unlocked. - If there are no timeouts rounding up we should never skip a round up. NOTE #1: In general trying to continue running after failing to round up CPUs doesn't appear to be supported in the debugger. When I simulate this I find that kdb reports "Catastrophic error detected" when I try to continue. I can overrule and continue anyway, but it should be noted that we may be entering the land of dragons here. Possibly the "Catastrophic error detected" was added _because_ of the future failure to round up, but even so this is an area of the code that hasn't been strongly tested. NOTE #2: I did a bit of testing before and after this change. I introduced a 10 second hang in the kernel while holding a spinlock that I could invoke on a certain CPU with 'taskset -c 3 cat /sys/...". Before this change if I did: - Invoke hang - Enter debugger - g (which warns about Catastrophic error, g again to go anyway) - g - Enter debugger ...I'd hang the rest of the 10 seconds without getting a debugger prompt. After this change I end up in the debugger the 2nd time after only 1 second with the standard warning about 'Timed out waiting for secondary CPUs.' I'll also note that once the CPU finished waiting I could actually debug it (aka "btc" worked) I won't promise that everything works perfectly if the errant CPU comes back at just the wrong time (like as we're entering or exiting the debugger) but it certainly seems like an improvement. NOTE #3: setting 'kgdb_info[cpu].rounding_up = false' is in kgdb_nmicallback() instead of kgdb_call_nmi_hook() because some implementations override kgdb_call_nmi_hook(). It shouldn't hurt to have it in kgdb_nmicallback() in any case. NOTE #4: this logic is really only needed because there is no API call like "smp_try_call_function_single_async()" or "smp_csd_is_locked()". If such an API existed then we'd use it instead, but it seemed a bit much to add an API like this just for kgdb. Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-12-30kgdb: Fix kgdb_roundup_cpus() for arches who used smp_call_function()Douglas Anderson1-0/+41
When I had lockdep turned on and dropped into kgdb I got a nice splat on my system. Specifically it hit: DEBUG_LOCKS_WARN_ON(current->hardirq_context) Specifically it looked like this: sysrq: SysRq : DEBUG ------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(current->hardirq_context) WARNING: CPU: 0 PID: 0 at .../kernel/locking/lockdep.c:2875 lockdep_hardirqs_on+0xf0/0x160 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.0 #27 pstate: 604003c9 (nZCv DAIF +PAN -UAO) pc : lockdep_hardirqs_on+0xf0/0x160 ... Call trace: lockdep_hardirqs_on+0xf0/0x160 trace_hardirqs_on+0x188/0x1ac kgdb_roundup_cpus+0x14/0x3c kgdb_cpu_enter+0x53c/0x5cc kgdb_handle_exception+0x180/0x1d4 kgdb_compiled_brk_fn+0x30/0x3c brk_handler+0x134/0x178 do_debug_exception+0xfc/0x178 el1_dbg+0x18/0x78 kgdb_breakpoint+0x34/0x58 sysrq_handle_dbg+0x54/0x5c __handle_sysrq+0x114/0x21c handle_sysrq+0x30/0x3c qcom_geni_serial_isr+0x2dc/0x30c ... ... irq event stamp: ...45 hardirqs last enabled at (...44): [...] __do_softirq+0xd8/0x4e4 hardirqs last disabled at (...45): [...] el1_irq+0x74/0x130 softirqs last enabled at (...42): [...] _local_bh_enable+0x2c/0x34 softirqs last disabled at (...43): [...] irq_exit+0xa8/0x100 ---[ end trace adf21f830c46e638 ]--- Looking closely at it, it seems like a really bad idea to be calling local_irq_enable() in kgdb_roundup_cpus(). If nothing else that seems like it could violate spinlock semantics and cause a deadlock. Instead, let's use a private csd alongside smp_call_function_single_async() to round up the other CPUs. Using smp_call_function_single_async() doesn't require interrupts to be enabled so we can remove the offending bit of code. In order to avoid duplicating this across all the architectures that use the default kgdb_roundup_cpus(), we'll add a "weak" implementation to debug_core.c. Looking at all the people who previously had copies of this code, there were a few variants. I've attempted to keep the variants working like they used to. Specifically: * For arch/arc we passed NULL to kgdb_nmicallback() instead of get_irq_regs(). * For arch/mips there was a bit of extra code around kgdb_nmicallback() NOTE: In this patch we will still get into trouble if we try to round up a CPU that failed to round up before. We'll try to round it up again and potentially hang when we try to grab the csd lock. That's not new behavior but we'll still try to do better in a future patch. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-12-30kgdb: Remove irq flags from roundupDouglas Anderson1-1/+1
The function kgdb_roundup_cpus() was passed a parameter that was documented as: > the flags that will be used when restoring the interrupts. There is > local_irq_save() call before kgdb_roundup_cpus(). Nobody used those flags. Anyone who wanted to temporarily turn on interrupts just did local_irq_enable() and local_irq_disable() without looking at them. So we can definitely remove the flags. Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: kdb_support: mark expected switch fall-throughsGustavo A. R. Silva1-3/+3
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Notice that in this particular case, I replaced the code comments with a proper "fall through" annotation, which is what GCC is expecting to find. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: kdb_keyboard: mark expected switch fall-throughsGustavo A. R. Silva1-2/+2
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Notice that in this particular case, I replaced the code comments with a proper "fall through" annotation, which is what GCC is expecting to find. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: kdb_main: refactor code in kdb_md_lineGustavo A. R. Silva1-18/+3
Replace the whole switch statement with a for loop. This makes the code clearer and easy to read. This also addresses the following Coverity warnings: Addresses-Coverity-ID: 115090 ("Missing break in switch") Addresses-Coverity-ID: 115091 ("Missing break in switch") Addresses-Coverity-ID: 114700 ("Missing break in switch") Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> [daniel.thompson@linaro.org: Tiny grammar change in description] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: Use strscpy with destination buffer sizePrarit Bhargava3-12/+15
gcc 8.1.0 warns with: kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’: kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=] strncpy(prefix_name, name, strlen(name)+1); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/debug/kdb/kdb_support.c:239:31: note: length computed here Use strscpy() with the destination buffer size, and use ellipses when displaying truncated symbols. v2: Use strscpy() Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Jonathan Toppins <jtoppins@redhat.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: kgdb-bugreport@lists.sourceforge.net Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: print real address of pointers instead of hashed addressesChristophe Leroy2-13/+13
Since commit ad67b74d2469 ("printk: hash addresses printed with %p"), all pointers printed with %p are printed with hashed addresses instead of real addresses in order to avoid leaking addresses in dmesg and syslog. But this applies to kdb too, with is unfortunate: Entering kdb (current=0x(ptrval), pid 329) due to Keyboard Entry kdb> ps 15 sleeping system daemon (state M) processes suppressed, use 'ps A' to see all. Task Addr Pid Parent [*] cpu State Thread Command 0x(ptrval) 329 328 1 0 R 0x(ptrval) *sh 0x(ptrval) 1 0 0 0 S 0x(ptrval) init 0x(ptrval) 3 2 0 0 D 0x(ptrval) rcu_gp 0x(ptrval) 4 2 0 0 D 0x(ptrval) rcu_par_gp 0x(ptrval) 5 2 0 0 D 0x(ptrval) kworker/0:0 0x(ptrval) 6 2 0 0 D 0x(ptrval) kworker/0:0H 0x(ptrval) 7 2 0 0 D 0x(ptrval) kworker/u2:0 0x(ptrval) 8 2 0 0 D 0x(ptrval) mm_percpu_wq 0x(ptrval) 10 2 0 0 D 0x(ptrval) rcu_preempt The whole purpose of kdb is to debug, and for debugging real addresses need to be known. In addition, data displayed by kdb doesn't go into dmesg. This patch replaces all %p by %px in kdb in order to display real addresses. Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Cc: <stable@vger.kernel.org> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-11-13kdb: use correct pointer when 'btc' calls 'btt'Christophe Leroy1-2/+2
On a powerpc 8xx, 'btc' fails as follows: Entering kdb (current=0x(ptrval), pid 282) due to Keyboard Entry kdb> btc btc: cpu status: Currently on cpu 0 Available cpus: 0 kdb_getarea: Bad address 0x0 when booting the kernel with 'debug_boot_weak_hash', it fails as well Entering kdb (current=0xba99ad80, pid 284) due to Keyboard Entry kdb> btc btc: cpu status: Currently on cpu 0 Available cpus: 0 kdb_getarea: Bad address 0xba99ad80 On other platforms, Oopses have been observed too, see https://github.com/linuxppc/linux/issues/139 This is due to btc calling 'btt' with %p pointer as an argument. This patch replaces %p by %px to get the real pointer value as expected by 'btt' Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Cc: <stable@vger.kernel.org> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2018-10-26sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOADJohannes Weiner1-6/+1
There are several definitions of those functions/macros in places that mess with fixed-point load averages. Provide an official version. [akpm@linux-foundation.org: fix missed conversion in block/blk-iolatency.c] Link: http://lkml.kernel.org/r/20180828172258.3185-5-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Daniel Drake <drake@endlessm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-12treewide: kzalloc() -> kcalloc()Kees Cook1-1/+1
The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12treewide: kmalloc() -> kmalloc_array()Kees Cook1-4/+7
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-04-12Merge tag 'for_linus-4.16' of ↵Linus Torvalds3-53/+44
git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb Pull kdb updates from Jason Wessel: - fix 2032 time access issues and new compiler warnings - minor regression test cleanup - formatting fixes for end user use of kdb * tag 'for_linus-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb: kdb: use memmove instead of overlapping memcpy kdb: use ktime_get_mono_fast_ns() instead of ktime_get_ts() kdb: bl: don't use tab character in output kdb: drop newline in unknown command output kdb: make "mdr" command repeat kdb: use __ktime_get_real_seconds instead of __current_kernel_time misc: kgdbts: Display progress of asynchronous tests
2018-02-04kdb: use memmove instead of overlapping memcpyArnd Bergmann1-2/+2
gcc discovered that the memcpy() arguments in kdbnearsym() overlap, so we should really use memmove(), which is defined to handle that correctly: In function 'memcpy', inlined from 'kdbnearsym' at /git/arm-soc/kernel/debug/kdb/kdb_support.c:132:4: /git/arm-soc/include/linux/string.h:353:9: error: '__builtin_memcpy' accessing 792 bytes at offsets 0 and 8 overlaps 784 bytes at offset 8 [-Werror=restrict] return __builtin_memcpy(p, q, size); Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-31kdb: use ktime_get_mono_fast_ns() instead of ktime_get_ts()Baolin Wang1-3/+3
The kdb code will print the monotonic time by ktime_get_ts(), but the ktime_get_ts() will be protected by a sequence lock, that will introduce one deadlock risk if the lock was already held in the context from which we entered the debugger. Thus we can use the ktime_get_mono_fast_ns() to get the monotonic time, which is NMI safe access to clock monotonic. Moreover we can remove the 'struct timespec', which is not y2038 safe. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-25kdb: bl: don't use tab character in outputRandy Dunlap1-2/+2
The "bl" (list breakpoints) command prints a '\t' (tab) character in its output, but on a console (video device), that just prints some odd graphics character. Instead of printing a tab character, just align the output with spaces. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-25kdb: drop newline in unknown command outputRandy Dunlap1-0/+11
When an unknown command is entered, kdb prints "Unknown kdb command:" and then the unknown text, including the newline character. This causes the ending single-quote mark to be printed on the next line by itself, so just change the ending newline character to a null character (end of string) so that it won't be "printed." Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-25kdb: make "mdr" command repeatRandy Dunlap1-6/+21
The "mdr" command should repeat (continue) when only Enter/Return is pressed, so make it do so. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-25kdb: use __ktime_get_real_seconds instead of __current_kernel_timeArnd Bergmann1-40/+5
kdb is the only user of the __current_kernel_time() interface, which is not y2038 safe and should be removed at some point. The kdb code also goes to great lengths to print the time in a human-readable format from 'struct timespec', again using a non-y2038-safe re-implementation of the generic time_to_tm() code. Using __current_kernel_time() here is necessary since the regular accessors that require a sequence lock might hang when called during the xtime update. However, this is safe in the particular case since kdb is only interested in the tv_sec field that is updated atomically. In order to make this y2038-safe, I'm converting the code to the generic time64_to_tm helper, but that introduces the problem that we have no interface like __current_kernel_time() that provides a 64-bit timestamp in a lockless, safe and architecture-independent way. I have multiple ideas for how to solve that: - __ktime_get_real_seconds() is lockless, but can return incorrect results on 32-bit architectures in the special case that we are in the process of changing the time across the epoch, either during the timer tick that overflows the seconds in 2038, or while calling settimeofday. - ktime_get_real_fast_ns() would work in this context, but does require a call into the clocksource driver to return a high-resolution timestamp. This may have undesired side-effects in the debugger, since we want to limit the interactions with the rest of the kernel. - Adding a ktime_get_real_fast_seconds() based on tk_fast_mono plus tkr->base_real without the tk_clock_read() delta. Not sure about the value of adding yet another interface here. - Changing the existing ktime_get_real_seconds() to use tk_fast_mono on 32-bit architectures rather than xtime_sec. I think this could work, but am not entirely sure if this is an improvement. I picked the first of those for simplicity here. It's technically not correct but probably good enough as the time is only used for the debugging output and the race will likely never be hit in practice. Another downside is having to move the declaration into a public header file. Let me know if anyone has a different preference. Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patchwork.kernel.org/patch/9775309/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2018-01-03signal: Simplify and fix kdb_send_sigEric W. Biederman2-9/+3
- Rename from kdb_send_sig_info to kdb_send_sig As there is no meaningful siginfo sent - Use SEND_SIG_PRIV instead of generating a siginfo for a kdb signal. The generated siginfo had a bogus rationale and was not correct in the face of pid namespaces. SEND_SIG_PRIV is simpler and actually correct. - As the code grabs siglock just send the signal with siglock held instead of dropping siglock and attempting to grab it again. - Move the sig_valid test into kdb_kill where it can generate a good error message. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2017-12-06kdb: Fix handling of kallsyms_symbol_next() return valueDaniel Thompson1-1/+1
kallsyms_symbol_next() returns a boolean (true on success). Currently kdb_read() tests the return value with an inequality that unconditionally evaluates to true. This is fixed in the obvious way and, since the conditional branch is supposed to be unreachable, we also add a WARN_ON(). Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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