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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-07-25 14:25:47 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-07-25 14:25:47 -0700 |
commit | fbe0d451bcea569fc0ed3455511a90646c8a9c81 (patch) | |
tree | eaa6b911fd789c51d514a2c7e82b1727bc33f8a3 /arch/x86/kernel/unwind_orc.c | |
parent | 78b1afe22d51996c1916a332d43b853ff2b10ade (diff) | |
parent | d181d2da0141371bbc360eaea78719203e165e1c (diff) | |
download | linux-fbe0d451bcea569fc0ed3455511a90646c8a9c81.tar.bz2 |
Merge tag 'x86-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- Fix a section end page alignment assumption that was causing
crashes
- Fix ORC unwinding on freshly forked tasks which haven't executed
yet and which have empty user task stacks
- Fix the debug.exception-trace=1 sysctl dumping of user stacks,
which was broken by recent maccess changes"
* tag 'x86-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/dumpstack: Dump user space code correctly again
x86/stacktrace: Fix reliable check for empty user task stacks
x86/unwind/orc: Fix ORC for newly forked tasks
x86, vmlinux.lds: Page-align end of ..page_aligned sections
Diffstat (limited to 'arch/x86/kernel/unwind_orc.c')
-rw-r--r-- | arch/x86/kernel/unwind_orc.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 7f969b2d240f..ec88bbe08a32 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -440,8 +440,11 @@ bool unwind_next_frame(struct unwind_state *state) /* * Find the orc_entry associated with the text address. * - * Decrement call return addresses by one so they work for sibling - * calls and calls to noreturn functions. + * For a call frame (as opposed to a signal frame), state->ip points to + * the instruction after the call. That instruction's stack layout + * could be different from the call instruction's layout, for example + * if the call was to a noreturn function. So get the ORC data for the + * call instruction itself. */ orc = orc_find(state->signal ? state->ip : state->ip - 1); if (!orc) { @@ -662,6 +665,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, state->sp = task->thread.sp; state->bp = READ_ONCE_NOCHECK(frame->bp); state->ip = READ_ONCE_NOCHECK(frame->ret_addr); + state->signal = (void *)state->ip == ret_from_fork; } if (get_stack_info((unsigned long *)state->sp, state->task, |