diff options
| author | Tomislav Novak <tnovak@fb.com> | 2022-09-26 18:09:12 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-12-14 13:37:15 +0300 |
| commit | d81c62e3121f365bfcc170d6208dc3fc597af20e (patch) | |
| tree | dd697c2e2147f0e18ad5d54dd0c11d2e281caaf8 | |
| parent | 66717ad03b80802752c9931afeedfcbd6806a8c2 (diff) | |
| download | linux-d81c62e3121f365bfcc170d6208dc3fc597af20e.tar.xz | |
ARM: 9251/1: perf: Fix stacktraces for tracepoint events in THUMB2 kernels
[ Upstream commit 612695bccfdbd52004551308a55bae410e7cd22f ]
Store the frame address where arm_get_current_stackframe() looks for it
(ARM_r7 instead of ARM_fp if CONFIG_THUMB2_KERNEL=y). Otherwise frame->fp
gets set to 0, causing unwind_frame() to fail.
# bpftrace -e 't:sched:sched_switch { @[kstack] = count(); exit(); }'
Attaching 1 probe...
@[
__schedule+1059
]: 1
A typical first unwind instruction is 0x97 (SP = R7), so after executing
it SP ends up being 0 and -URC_FAILURE is returned.
unwind_frame(pc = ac9da7d7 lr = 00000000 sp = c69bdda0 fp = 00000000)
unwind_find_idx(ac9da7d7)
unwind_exec_insn: insn = 00000097
unwind_exec_insn: fp = 00000000 sp = 00000000 lr = 00000000 pc = 00000000
With this patch:
# bpftrace -e 't:sched:sched_switch { @[kstack] = count(); exit(); }'
Attaching 1 probe...
@[
__schedule+1059
__schedule+1059
schedule+79
schedule_hrtimeout_range_clock+163
schedule_hrtimeout_range+17
ep_poll+471
SyS_epoll_wait+111
sys_epoll_pwait+231
__ret_fast_syscall+1
]: 1
Link: https://lore.kernel.org/r/20220920230728.2617421-1-tnovak@fb.com/
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tomislav Novak <tnovak@fb.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/arm/include/asm/perf_event.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h index fe87397c3d8c..bdbc1e590891 100644 --- a/arch/arm/include/asm/perf_event.h +++ b/arch/arm/include/asm/perf_event.h @@ -17,7 +17,7 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); #define perf_arch_fetch_caller_regs(regs, __ip) { \ (regs)->ARM_pc = (__ip); \ - (regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \ + frame_pointer((regs)) = (unsigned long) __builtin_frame_address(0); \ (regs)->ARM_sp = current_stack_pointer; \ (regs)->ARM_cpsr = SVC_MODE; \ } |