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 4DCAB171CD for ; Mon, 25 Nov 2024 15:21:05 +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=1732548065; cv=none; b=bPuOOqIsIv3CilqMazXOUpf63IfWwlhUnFRg0SO0UtSJb3b2ogBWTbQMmobDxWGfzVmOXfmTwCDMhvITpjBnfIEUSAH3VLLAjcovt/0Fc2gVGwmaXeU5C+K+r6YKS01ASCOTBlYXPL8HYCrD4Iy0dPEhuydHhkemI0mawINp7IE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732548065; c=relaxed/simple; bh=UfpqlpzDYfEINtVE5bruFEPxx0wC3IC10RqoP8Mgx8M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BEc4/eiNi68taPZCtS7E8gmOMieiahD1NUCHc+kTkXL/5u3MBdCHTQadYvrr7eTbgUyU8JzhZD1MoPTCkgQlelnxm/BOHlTMSpzYvF+D5jQc33x377Yn1laRexALsTJSBy9eVLk/J3dGw5PRAI5KNa8OPu6+MylED0p7ND+Y79w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c3tFamwj; 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="c3tFamwj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF25EC4CECE; Mon, 25 Nov 2024 15:21:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732548065; bh=UfpqlpzDYfEINtVE5bruFEPxx0wC3IC10RqoP8Mgx8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c3tFamwjst52QDgc5FO3HYwcrbVJxRydMB5rrknuCtCmXQXyF4pHkaO/wN6AHlyrT a2avhIjvGfopWFKhChGR5MPH2/idzEkEBd2Rq2UjZguEguJVkjfNrQ3CLbh0G9di+g 0hE9vj9UmUKx9SCTErAKILbCMKeGrQtBOKUtUgeATPQvYTMU5CJw34Mes96ChGvTcF YSXcfiPjrRQM2M6sVo+VNnWTeEw1vRzBlMsEzfADyI9LdrcEbPxUdzr1aIKHk3tIk1 HbqAEE6XlvU2GoF9e/HwCRBtqb3P7L8EE2Xju4YFIPnIxJ6pWpHk6bD5cFAsM86fvh 28QeHfEOxm5Eg== From: Sasha Levin To: stable@vger.kernel.org Cc: Bin Lan , Sasha Levin Subject: Re: [PATCH 6.6] fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats Date: Mon, 25 Nov 2024 10:21:03 -0500 Message-ID: <20241125090126-a7ecce7ce5adb98d@stable.kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241125053307.374219-1-bin.lan.cn@windriver.com> References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit [ Sasha's backport helper bot ] Hi, The upstream commit SHA1 provided is correct: 7601df8031fd67310af891897ef6cc0df4209305 WARNING: Author mismatch between patch and upstream commit: Backport author: Bin Lan Commit author: Oleg Nesterov Status in newer kernel trees: 6.12.y | Present (exact SHA1) 6.11.y | Present (exact SHA1) 6.6.y | Not found Note: The patch differs from the upstream commit: --- --- - 2024-11-25 08:56:48.440504041 -0500 +++ /tmp/tmp.DBppGejMK4 2024-11-25 08:56:48.433034088 -0500 @@ -1,3 +1,5 @@ +[ Upstream commit 7601df8031fd67310af891897ef6cc0df4209305 ] + lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call do_task_stat() at the same time and the process has NR_THREADS, it will spin with irqs disabled O(NR_CPUS * NR_THREADS) time. @@ -12,12 +14,14 @@ Cc: Eric W. Biederman Cc: Signed-off-by: Andrew Morton +[ Resolve minor conflicts ] +Signed-off-by: Bin Lan --- - fs/proc/array.c | 58 +++++++++++++++++++++++++++---------------------- - 1 file changed, 32 insertions(+), 26 deletions(-) + fs/proc/array.c | 57 +++++++++++++++++++++++++++---------------------- + 1 file changed, 32 insertions(+), 25 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c -index 45ba918638084..34a47fb0c57f2 100644 +index 37b8061d84bb..34a47fb0c57f 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -477,13 +477,13 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, @@ -51,7 +55,7 @@ if (sig->tty) { struct pid *pgrp = tty_get_pgrp(sig->tty); tty_pgrp = pid_nr_ns(pgrp, ns); -@@ -527,27 +523,9 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, +@@ -527,26 +523,9 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, num_threads = get_nr_threads(task); collect_sigign_sigcatch(task, &sigign, &sigcatch); @@ -64,13 +68,12 @@ - /* add up live thread stats at the group level */ if (whole) { -- struct task_struct *t; -- -- __for_each_thread(sig, t) { +- struct task_struct *t = task; +- do { - min_flt += t->min_flt; - maj_flt += t->maj_flt; - gtime += task_gtime(t); -- } +- } while_each_thread(task, t); - - min_flt += sig->min_flt; - maj_flt += sig->maj_flt; @@ -79,7 +82,7 @@ if (sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_STOP_STOPPED)) exit_code = sig->group_exit_code; } -@@ -562,6 +540,34 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, +@@ -561,6 +540,34 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, if (permitted && (!whole || num_threads < 2)) wchan = !task_is_running(task); @@ -114,3 +117,6 @@ if (whole) { thread_group_cputime_adjusted(task, &utime, &stime); } else { +-- +2.43.0 + --- Results of testing on various branches: | Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.6.y | Success | Success |