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x86: Fix __get_wchan() for !STACKTRACE

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Use asm/unwind.h to implement wchan, since we cannot always rely on
STACKTRACE=y.

Fixes: bc9bbb8173 ("x86: Fix get_wchan() to support the ORC unwinder")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20211022152104.137058575@infradead.org
This commit is contained in:
Peter Zijlstra 2021-10-22 16:53:02 +02:00
parent 55409ac5c3
commit 5d1ceb3969
1 changed files with 14 additions and 3 deletions
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17
arch/x86/kernel/process.c
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@ -43,6 +43,7 @@
#include <asm/io_bitmap.h>
#include <asm/proto.h>
#include <asm/frame.h>
#include <asm/unwind.h>
#include "process.h"
@ -944,10 +945,20 @@ 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,