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 798EC14388D; Tue, 23 Apr 2024 21:41:45 +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=1713908505; cv=none; b=rXfuyV9XR05wcC54klvUsYzLLcPZKJq96+jfjudm25uQzIaglkeV6HCPxKaJZLFDx7f1mPYBkLmRyydyTq9XbRGmKbvnkEi6saEvelFTwLRdLsRm35tem5nBlmDb5rPelgL0rxHn67UULHumWtzJDNWkdTtUHXv+X39zB0Vpiwg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908505; c=relaxed/simple; bh=CExlSkHgH0tyCbljyaKTd5oE2X8dmxwpHc61O1PkWUs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O6R8B02pCpJLhOH8WQQoJN6o/I2DlbGD+VoYIHCm4gVCUC13wD3DQ3/cB7vcKeBtyA44BW2UkvgRZt7OvkYWVqkw5LL5KqzZnbuxFyyYyzvj5vfWeAtIVFqSGa5wuWM+XAIlZQOVQHnheH/j3Ft8yxYS8CM0vnBnXQdRDAbxk2s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LlOD8sg/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LlOD8sg/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DB23C32783; Tue, 23 Apr 2024 21:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908505; bh=CExlSkHgH0tyCbljyaKTd5oE2X8dmxwpHc61O1PkWUs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LlOD8sg/6ximsKtgmGyO57L6OrMAAqBu3CrTMql5sy5W8T4ExRsI4BnVReiZ1b9G1 nIiHBbHUYqhL50rwSWL6YWeLmyaXafn8wM67zKi6XNlK7FHdj/A7FG5VHce8rfsKnE c4lMUwdQFtGM8Csyuhmx4j5Djykz1QaoozTt+//E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Arnaldo Carvalho de Melo , Song Liu , bpf@vger.kernel.org, Namhyung Kim , Sasha Levin Subject: [PATCH 6.8 059/158] perf lock contention: Add a missing NULL check Date: Tue, 23 Apr 2024 14:38:01 -0700 Message-ID: <20240423213857.872307501@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.824778126@linuxfoundation.org> References: <20240423213855.824778126@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Namhyung Kim [ Upstream commit f3408580bac8ce5cd76e7391e529c0a22e7c7eb2 ] I got a report for a failure in BPF verifier on a recent kernel with perf lock contention command. It checks task->sighand->siglock without checking if sighand is NULL or not. Let's add one. ; if (&curr->sighand->siglock == (void *)lock) 265: (79) r1 = *(u64 *)(r0 +2624) ; frame1: R0_w=trusted_ptr_task_struct(off=0,imm=0) ; R1_w=rcu_ptr_or_null_sighand_struct(off=0,imm=0) 266: (b7) r2 = 0 ; frame1: R2_w=0 267: (0f) r1 += r2 R1 pointer arithmetic on rcu_ptr_or_null_ prohibited, null-check it first processed 164 insns (limit 1000000) max_states_per_insn 1 total_states 15 peak_states 15 mark_read 5 -- END PROG LOAD LOG -- libbpf: prog 'contention_end': failed to load: -13 libbpf: failed to load object 'lock_contention_bpf' libbpf: failed to load BPF skeleton 'lock_contention_bpf': -13 Failed to load lock-contention BPF skeleton lock contention BPF setup failed lock contention did not detect any lock contention Fixes: 1811e82767dcc ("perf lock contention: Track and show siglock with address") Reviewed-by: Ian Rogers Acked-by: Arnaldo Carvalho de Melo Cc: Song Liu Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240409225542.1870999-1-namhyung@kernel.org Signed-off-by: Sasha Levin --- tools/perf/util/bpf_skel/lock_contention.bpf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 95cd8414f6ef8..e5d78565f479f 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -289,6 +289,7 @@ static inline __u32 check_lock_type(__u64 lock, __u32 flags) struct task_struct *curr; struct mm_struct___old *mm_old; struct mm_struct___new *mm_new; + struct sighand_struct *sighand; switch (flags) { case LCB_F_READ: /* rwsem */ @@ -310,7 +311,9 @@ static inline __u32 check_lock_type(__u64 lock, __u32 flags) break; case LCB_F_SPIN: /* spinlock */ curr = bpf_get_current_task_btf(); - if (&curr->sighand->siglock == (void *)lock) + sighand = curr->sighand; + + if (sighand && &sighand->siglock == (void *)lock) return LCD_F_SIGHAND_LOCK; break; default: -- 2.43.0