Re: [PATCH v3 6/9] arm64: Recover kretprobe modified return address in stacktrace
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: 2021-10-21 14:27:07
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On Thu, 21 Oct 2021 11:15:12 +0100 Will Deacon [off-list ref] wrote:
On Thu, Oct 21, 2021 at 09:55:09AM +0900, Masami Hiramatsu wrote:quoted
Since the kretprobe replaces the function return address with the kretprobe_trampoline on the stack, stack unwinder shows it instead of the correct return address. This checks whether the next return address is the __kretprobe_trampoline(), and if so, try to find the correct return address from the kretprobe instance list. For this purpose this adds 'kr_cur' loop cursor to memorize the current kretprobe instance. With this fix, now arm64 can enable CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE, and pass the kprobe self tests. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- Changes in v2: - Add comment for kr_cur. - Make the kretprobe related code depends on CONFIG_KRETPROBES. - Initialize "kr_cur" directly in start_backtrace() instead of clearing "frame" data structure by memset(). --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/stacktrace.h | 4 ++++ arch/arm64/kernel/stacktrace.c | 7 +++++++ 3 files changed, 12 insertions(+)Acked-by: Will Deacon <will@kernel.org>
Thank you!
I'm not sure how you're planning to merge this, so please let me know if you want me to queue any of the arm64 bits.
Ah, good question. Since this part depends on the first 3 patches and Steve's tracing tree, these should go through the tracing tree. Is that OK for you? (Or, wait for merging the current tracing tree and merge rest of them. but this will take a long time.) Thank you, -- Masami Hiramatsu [off-list ref] _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel