On Mon, 22 Mar 2021 at 16:57, Ard Biesheuvel <a...@kernel.org> wrote: > > On Mon, 22 Mar 2021 at 14:26, Will Deacon <w...@kernel.org> wrote: > > > > On Fri, 19 Mar 2021 18:41:06 +0000, Mark Rutland wrote: > > > We recently converted arm64 to use arch_stack_walk() in commit: > > > > > > 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK") > > > > > > The core stacktrace code expects that (when tracing the current task) > > > arch_stack_walk() starts a trace at its caller, and does not include > > > itself in the trace. However, arm64's arch_stack_walk() includes itself, > > > and so traces include one more entry than callers expect. The core > > > stacktrace code which calls arch_stack_walk() tries to skip a number of > > > entries to prevent itself appearing in a trace, and the additional entry > > > prevents skipping one of the core stacktrace functions, leaving this in > > > the trace unexpectedly. > > > > > > [...] > > > > Applied to arm64 (for-next/fixes), thanks! > > > > [1/1] arm64: stacktrace: don't trace arch_stack_walk() > > https://git.kernel.org/arm64/c/c607ab4f916d > > > > Ehm, did anyone check if the following caveat regarding > __builtin_frame_address() applies on arm64? (from the GCC man page > [0]) > > """ > Calling this function with a nonzero argument can have unpredictable > effects, including crashing the calling program. As a result, calls > that are considered unsafe are diagnosed when the -Wframe-address > option is in effect. Such calls should only be made in debugging > situations. > """ > > [0] https://gcc.gnu.org/onlinedocs/gcc/Return-Address.html
Never mind, failed to read the entire thread. Apologies ...