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 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 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,