arm64: stacktrace: Report when we reach the end of the stack
PATCH RESEND 1/1 arm64: stacktrace: Report when we reach the end of the stack
Currently the arm64 unwinder code returns -EINVAL whenever it can't find the next stack frame, not distinguishing between cases where the stack has been corrupted or is otherwise in a state it shouldn't be and cases where we have reached the end of the stack. At the minute none of the callers care what error code is returned but this will be important for reliable stack trace which needs to be sure that the stack is intact.
Change to return -ENOENT in the case where we reach the bottom of the stack. The error codes from this function are only used in kernel, this particular code is chosen as we are indicating that we know there is no frame there.
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Resending this separately from the wider series it was originally sent in as it came up in discussion of Madhavan's series earlier today - we could probably just apply this as is since it seems like we'll want it regardless of how reliable stacktrace ends up being implemented.
arch/arm64/kernel/stacktrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm64/kernel/stacktrace.c +1 -1
@@ -46,7 +46,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)/* Terminal record; nothing to unwind */ if (!fp) -return -EINVAL ; +return -ENOENT ;if (fp &0xf )return -EINVAL ;
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Quoted 8 lines · Mark Brown
Currently the arm64 unwinder code returns
-EINVALwhenever it can't find the next stack frame, not distinguishing between cases where the stack has been corrupted or is otherwise in a state it shouldn't be and cases where we have reached the end of the stack. At the minute none of the callers care what error code is returned but this will be important for reliable stack trace which needs to be sure that the stack is intact.[...]
Applied to arm64 (for-next/fixes), thanks!
[1/1] arm64: stacktrace: Report when we reach the end of the stack
https://git.kernel.org/arm64/c/3c02600144bd
Cheers,
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Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev _______________________________________________ linux-arm-kernel mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-arm-kernel