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authorMasami Hiramatsu <mhiramat@kernel.org>2021-10-21 09:55:17 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-11-18 19:16:19 +0100
commit7d341b27013e183e002043b2ec0db6ec6f24fa80 (patch)
tree9e4ed37f6aa2212c0c6fd14352073a187d890b40 /arch
parent7f11e51f0c9d158e06eb240b5316b60e80a49fc1 (diff)
ARM: clang: Do not rely on lr register for stacktrace
[ Upstream commit b3ea5d56f212ad81328c82454829a736197ebccc ] Currently the stacktrace on clang compiled arm kernel uses the 'lr' register to find the first frame address from pt_regs. However, that is wrong after calling another function, because the 'lr' register is used by 'bl' instruction and never be recovered. As same as gcc arm kernel, directly use the frame pointer (r11) of the pt_regs to find the first frame address. Note that this fixes kretprobe stacktrace issue only with CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM, we need another fix. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kernel/stacktrace.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 76ea4178a55c..db798eac7431 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -54,8 +54,7 @@ int notrace unwind_frame(struct stackframe *frame)
frame->sp = frame->fp;
frame->fp = *(unsigned long *)(fp);
- frame->pc = frame->lr;
- frame->lr = *(unsigned long *)(fp + 4);
+ frame->pc = *(unsigned long *)(fp + 4);
#else
/* check current frame pointer is within bounds */
if (fp < low + 12 || fp > high - 4)