[PATCH 5.15 528/917] x86: Fix __get_wchan() for !STACKTRACE
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-11-15 23:47:35
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Peter Zijlstra <peterz@infradead.org>
[ Upstream commit 5d1ceb3969b6b2e47e2df6d17790a7c5a20fcbb4 ]
Use asm/unwind.h to implement wchan, since we cannot always rely on
STACKTRACE=y.
Fixes: bc9bbb81730e ("x86: Fix get_wchan() to support the ORC unwinder")
Reported-by: Stephen Rothwell <redacted>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <redacted>
Link: https://lkml.kernel.org/r/20211022152104.137058575@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kernel/process.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 266962547b58c..2fe1810e922a9 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c@@ -43,6 +43,7 @@ #include <asm/io_bitmap.h> #include <asm/proto.h> #include <asm/frame.h> +#include <asm/unwind.h> #include "process.h"
@@ -945,10 +946,20 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) */ unsigned long __get_wchan(struct task_struct *p) { - unsigned long entry = 0; + struct unwind_state state; + unsigned long addr = 0; - stack_trace_save_tsk(p, &entry, 1, 0); - return entry; + for (unwind_start(&state, p, NULL, NULL); !unwind_done(&state); + unwind_next_frame(&state)) { + addr = unwind_get_return_address(&state); + if (!addr) + break; + if (in_sched_functions(addr)) + continue; + break; + } + + return addr; } long do_arch_prctl_common(struct task_struct *task, int option,
--
2.33.0