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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-12 20:04:15 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-12 20:04:15 -0800 |
commit | c17488d06666153a14dd3f21bd10eba58383f6c1 (patch) | |
tree | 8a8dfaa2b2692f8b4eb20fe7e4266036f692fbdc /arch/x86/kernel | |
parent | 34a9304a96d6351c2d35dcdc9293258378fc0bd8 (diff) | |
parent | 5156dca34a3e1e1edac2d0dabf43d8632909b7aa (diff) | |
download | linux-c17488d06666153a14dd3f21bd10eba58383f6c1.tar.bz2 |
Merge tag 'trace-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Not much new with tracing for this release. Mostly just clean ups and
minor fixes.
Here's what else is new:
- A new TRACE_EVENT_FN_COND macro, combining both _FN and _COND for
those that want both.
- New selftest to test the instance create and delete
- Better debug output when ftrace fails"
* tag 'trace-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (24 commits)
ftrace: Fix the race between ftrace and insmod
ftrace: Add infrastructure for delayed enabling of module functions
x86: ftrace: Fix the comments for ftrace_modify_code_direct()
tracing: Fix comment to use tracing_on over tracing_enable
metag: ftrace: Fix the comments for ftrace_modify_code
sh: ftrace: Fix the comments for ftrace_modify_code()
ia64: ftrace: Fix the comments for ftrace_modify_code()
ftrace: Clean up ftrace_module_init() code
ftrace: Join functions ftrace_module_init() and ftrace_init_module()
tracing: Introduce TRACE_EVENT_FN_COND macro
tracing: Use seq_buf_used() in seq_buf_to_user() instead of len
bpf: Constify bpf_verifier_ops structure
ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too
ftrace: Remove use of control list and ops
ftrace: Fix output of enabled_functions for showing tramp
ftrace: Fix a typo in comment
ftrace: Show all tramps registered to a record on ftrace_bug()
ftrace: Add variable ftrace_expected for archs to show expected code
ftrace: Add new type to distinguish what kind of ftrace_bug()
tracing: Update cond flag when enabling or disabling a trigger
...
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r-- | arch/x86/kernel/ftrace.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 311bcf338f07..29408d6d6626 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -105,14 +105,14 @@ ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code, { unsigned char replaced[MCOUNT_INSN_SIZE]; + ftrace_expected = old_code; + /* - * Note: Due to modules and __init, code can - * disappear and change, we need to protect against faulting - * as well as code changing. We do this by using the - * probe_kernel_* functions. - * - * No real locking needed, this code is run through - * kstop_machine, or before SMP starts. + * Note: + * We are paranoid about modifying text, as if a bug was to happen, it + * could cause us to read or write to someplace that could cause harm. + * Carefully read and modify the code with probe_kernel_*(), and make + * sure what we read is what we expected it to be before modifying it. */ /* read the text we want to modify */ @@ -154,6 +154,8 @@ int ftrace_make_nop(struct module *mod, if (addr == MCOUNT_ADDR) return ftrace_modify_code_direct(rec->ip, old, new); + ftrace_expected = NULL; + /* Normal cases use add_brk_on_nop */ WARN_ONCE(1, "invalid use of ftrace_make_nop"); return -EINVAL; @@ -220,6 +222,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { WARN_ON(1); + ftrace_expected = NULL; return -EINVAL; } @@ -314,6 +317,8 @@ static int add_break(unsigned long ip, const char *old) if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE)) return -EFAULT; + ftrace_expected = old; + /* Make sure it is what we expect it to be */ if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0) return -EINVAL; @@ -413,6 +418,8 @@ static int remove_breakpoint(struct dyn_ftrace *rec) ftrace_addr = ftrace_get_addr_curr(rec); nop = ftrace_call_replace(ip, ftrace_addr); + ftrace_expected = nop; + if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0) return -EINVAL; } |