From nobody Sat Feb 7 17:00:57 2026 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 15A9F2264DC; Thu, 30 Oct 2025 03:27:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761794834; cv=none; b=JXeqPZ73rPGRC1Ldh+CXQD95PoIJi03B1T3hppXbk+/paec00LzcYZ8DAbkpOfkXbBtW9kE7kmn6s1SPBkeHLBZF1m4fB7HdyKf3ajufnP1PE7Fko/gtbv1jPrSuKwunfmYIMFbibzoD4GbaoyBuR0HfKzERVpOKJuFKRlRt8YI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761794834; c=relaxed/simple; bh=cfhICDAycpdcZ0C2xlkyCdUlNHCGdRQjBFptHTiR07c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SGE7PQVirZfKXz8/LRtR22JGKq0vq0w1hRWKFPk0vkd3ITYhcNqVR3c6ViiRjQlvInQKc43TqsFmDSDMA7KdsGiW+48I66U9LoPLSMjj9ZqGw/pbutPexyhRwP9oNdrFTG/AlBHLlz4JCk9sng9FMHEGMWFGn++nmhcuKlGj9+0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q3leZ3EQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q3leZ3EQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6686C4CEFF; Thu, 30 Oct 2025 03:27:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761794833; bh=cfhICDAycpdcZ0C2xlkyCdUlNHCGdRQjBFptHTiR07c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q3leZ3EQv52ijoBcpC1BDyWPH5QcmZcnGd0YsDnPcBk8E4QDQXA1B4Iny+PMY0mNF evV8c9vtjwD693qQKwKaiueOvg2jyFVsgl53UpUzbdv8fFHjdXrQUQ2dsFm4ohwRfs AQUa/IPdbPamjlgf2YNgY0LZ5mWDnQ9n/UuuV3XEyPcbqt/DPrdJwmHHbz77nHJctX YBH0qaEA9otp/en9y/CiPWivt6DjAJh+MNhI9Xu9+fOjpeslkEh8PyvjE7WnMjHrVe eRTvWTFNvkQ/rMxLnksAkgvoFu53//RxqInaxN/RM2V/lQpn5Vp43T8n/CCmy3zRsX vMuVJZ5sIBsTw== From: "Masami Hiramatsu (Google)" To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Steven Rostedt Cc: Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Masami Hiramatsu , Mathieu Desnoyers , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] perf: Introduce default_overflow_compatible flag Date: Thu, 30 Oct 2025 12:27:07 +0900 Message-ID: <176179482721.959775.9568162681903659824.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176179481538.959775.12326313742393696258.stgit@devnote2> References: <176179481538.959775.12326313742393696258.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Instead of checking whether event->overflow_handler everytime in is_default_overflow_handler(), just use a flag to check it once when registering the handler. Signed-off-by: Masami Hiramatsu (Google) --- include/linux/perf_event.h | 9 ++------- kernel/events/core.c | 2 ++ 2 files changed, 4 insertions(+), 7 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index fd1d91017b99..40dd897e26b0 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -902,6 +902,7 @@ struct perf_event { u64 (*clock)(void); perf_overflow_handler_t overflow_handler; void *overflow_handler_context; + bool default_overflow_compatible; struct bpf_prog *prog; u64 bpf_cookie; =20 @@ -1505,13 +1506,7 @@ extern int perf_event_output(struct perf_event *even= t, static inline bool is_default_overflow_handler(struct perf_event *event) { - perf_overflow_handler_t overflow_handler =3D event->overflow_handler; - - if (likely(overflow_handler =3D=3D perf_event_output_forward)) - return true; - if (unlikely(overflow_handler =3D=3D perf_event_output_backward)) - return true; - return false; + return event->default_overflow_compatible; } =20 extern void diff --git a/kernel/events/core.c b/kernel/events/core.c index 177e57c1a362..6bbbde82cb21 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -12946,9 +12946,11 @@ perf_event_alloc(struct perf_event_attr *attr, int= cpu, } else if (is_write_backward(event)){ event->overflow_handler =3D perf_event_output_backward; event->overflow_handler_context =3D NULL; + event->default_overflow_compatible =3D true; } else { event->overflow_handler =3D perf_event_output_forward; event->overflow_handler_context =3D NULL; + event->default_overflow_compatible =3D true; } =20 perf_event__state_init(event); From nobody Sat Feb 7 17:00:57 2026 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 E13072264DC; Thu, 30 Oct 2025 03:27:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761794845; cv=none; b=fq1zzA2aLtwbGsky7DxmrxIP/qL8uPlfq/DTE/TWbH6jdBfl4ZtfPx6ox2IQduo4a8dpP1Kswh3nNnxpxlfe4KTrFktLcjpyRwnh0kzLvxSOh5Sbm2kieessAIrfxMU5i+tQZjxS//WHXogVr6eaKpS3FFWio6bj0Gw/y0VMsgE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761794845; c=relaxed/simple; bh=jJ98GA8lXMZB+PEb4XMuc+DVI+yBUyfVXN3flVjshBI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GxJbja+Ib7siGkKv3buQbbjPVQK19VSTHtytAKcLgyWUMMlg6Fy0mfg5m5eyrE8FmiocyKXPBVarKC22c2BeEylA5LLIhkV/3occP/qcu6lfpIHm7Kd8gjXbz62EScMxtfmv8KcZF2e7rlVhQOSv84QR+LGEp/sB4ZeQRUoIsPE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bPhrbrJK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bPhrbrJK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67336C4CEF7; Thu, 30 Oct 2025 03:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761794844; bh=jJ98GA8lXMZB+PEb4XMuc+DVI+yBUyfVXN3flVjshBI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bPhrbrJKxNk4PO3YGKRuaN44F7Ub0QfEnH8eiksF0Qmd1qeAp/bp+iKaa1pcD/lEY umPyzuyB31d/ubl88s5JEMbkoarzZf+ZEYo6jQDoafKfTKOjD44Z6rt0Y5ygQpnuK4 u7xolnYjGGpFv3E+2nNZkFROqo4NmRTzcvHA65hpWsJmeGIIE+MIgK9JgF7TBvzA3N LM8lHyfkURqAMHsWD8LAOLEX5NDX3my6BbmsqmEYmcf7KV/DVk4S+K80AKVqhhSUjD DQy64zffDRyTIHq9zO4iQYwS3FR/aYIh3DYB06HDJpPRPBLoF368p/YMsYNwspdUOf uCbSt1wrwDG6Q== From: "Masami Hiramatsu (Google)" To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Steven Rostedt Cc: Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Masami Hiramatsu , Mathieu Desnoyers , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/2] tracing: wprobe: Make wprobe_handler default overflow_handler compatible Date: Thu, 30 Oct 2025 12:27:19 +0900 Message-ID: <176179483888.959775.5748906728818431150.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <176179481538.959775.12326313742393696258.stgit@devnote2> References: <176179481538.959775.12326313742393696258.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) To fix arm64 repeating watchpoint exception on the same instruction bug, markthe wprobe handler as compatible with the default overflow handler. Since do_watchpoint() on arm64 does not configure the single step execution correctly if the overflow_handler is not compatible with default perf overflow handlers, custom handler will loop on the same instruction by repeating watchpoint exception. But if the overflow handler is compatible with the default handlers, it configures the single step. So set the compatible flag since wprobe_handler will not care arch-dependent case. Reported-by: Mark Brown Closes: https://lore.kernel.org/all/aPvwGhMBJqMKcC9D@finisterre.sirena.org.= uk/ Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_wprobe.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c index 98605b207f43..f2c2f26fd668 100644 --- a/kernel/trace/trace_wprobe.c +++ b/kernel/trace/trace_wprobe.c @@ -163,6 +163,8 @@ static void wprobe_perf_handler(struct perf_event *bp, static int __register_trace_wprobe(struct trace_wprobe *tw) { struct perf_event_attr attr; + struct perf_event *bp; + int cpu; =20 if (tw->bp_event) return -EINVAL; @@ -179,6 +181,11 @@ static int __register_trace_wprobe(struct trace_wprobe= *tw) tw->bp_event =3D NULL; return ret; } + /* Mark wprobe_perf_handler is compatible with default one. */ + for_each_online_cpu(cpu) { + bp =3D per_cpu(*tw->bp_event, cpu); + bp->default_overflow_compatible =3D true; + } =20 return 0; }