From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7425C28ED for ; Mon, 12 Dec 2022 13:54:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0B70C433EF; Mon, 12 Dec 2022 13:54:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670853288; bh=+5GGC/8eufWXSVnOGBvw3X8yB+l1PO1V+/FGgW8gFtc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rrlcJ6cn0XPA23NmOIiZpJGbG8QS8rvD95M19nFdbybJyAIup3mGQX9IP91P/gdVk v2yftgv28wAfX3+Agi1pe+l6tqE9hzsukIbYiX+wp4Lnvkb15HHEtglN4T7A4QnWnv h8lpq6xiRrPGyVfcLj40xWYqnZnC5toLSDaZXotk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Linus Walleij , Tomislav Novak , "Russell King (Oracle)" , Sasha Levin Subject: [PATCH 4.9 03/31] ARM: 9251/1: perf: Fix stacktraces for tracepoint events in THUMB2 kernels Date: Mon, 12 Dec 2022 14:19:21 +0100 Message-Id: <20221212130910.137612038@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130909.943483205@linuxfoundation.org> References: <20221212130909.943483205@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Tomislav Novak [ Upstream commit 612695bccfdbd52004551308a55bae410e7cd22f ] Store the frame address where arm_get_current_stackframe() looks for it (ARM_r7 instead of ARM_fp if CONFIG_THUMB2_KERNEL=y). Otherwise frame->fp gets set to 0, causing unwind_frame() to fail. # bpftrace -e 't:sched:sched_switch { @[kstack] = count(); exit(); }' Attaching 1 probe... @[ __schedule+1059 ]: 1 A typical first unwind instruction is 0x97 (SP = R7), so after executing it SP ends up being 0 and -URC_FAILURE is returned. unwind_frame(pc = ac9da7d7 lr = 00000000 sp = c69bdda0 fp = 00000000) unwind_find_idx(ac9da7d7) unwind_exec_insn: insn = 00000097 unwind_exec_insn: fp = 00000000 sp = 00000000 lr = 00000000 pc = 00000000 With this patch: # bpftrace -e 't:sched:sched_switch { @[kstack] = count(); exit(); }' Attaching 1 probe... @[ __schedule+1059 __schedule+1059 schedule+79 schedule_hrtimeout_range_clock+163 schedule_hrtimeout_range+17 ep_poll+471 SyS_epoll_wait+111 sys_epoll_pwait+231 __ret_fast_syscall+1 ]: 1 Link: https://lore.kernel.org/r/20220920230728.2617421-1-tnovak@fb.com/ Reviewed-by: Linus Walleij Signed-off-by: Tomislav Novak Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- arch/arm/include/asm/perf_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h index 4f9dec489931..c5d27140834e 100644 --- a/arch/arm/include/asm/perf_event.h +++ b/arch/arm/include/asm/perf_event.h @@ -21,7 +21,7 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); #define perf_arch_fetch_caller_regs(regs, __ip) { \ (regs)->ARM_pc = (__ip); \ - (regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \ + frame_pointer((regs)) = (unsigned long) __builtin_frame_address(0); \ (regs)->ARM_sp = current_stack_pointer; \ (regs)->ARM_cpsr = SVC_MODE; \ } -- 2.35.1