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 C703D4F602 for ; Fri, 16 Aug 2024 07:43:09 +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=1723794189; cv=none; b=FEra86zQlbwx6UPZqY4j/sIZ7Kz4ORLdR7Wd/kAcRgM7CJf+0H1mWavhDZm59INarMQH9YYy8laI6sYjnTfuzuSbXphbtLjV6MycGVvqGgsnH7NPxV0Cro/l2GSPdQR/MEn146bRQTSuMO8eJpolGucFL+gMokALoMZDv3tER2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723794189; c=relaxed/simple; bh=l3JZvIn/HnfiPn+23+JJ+7h32og1cXxHlFtmiqQph+w=; h=From:To:Subject:Date:Message-ID:Content-Type:MIME-Version; b=nT54Sch4IdhwNOJgUNb7dva0ntqnv3ivOR49nDAYrR0KeV4irSBfqmTRLnYPVXKPpmLL8z6RWCrFmWIHAeSRODVKXagM+TOk0OnU34BK3Q4iyL9kAkgFsBHwX418OpT9T/7Xnqam+pq9wb9CbGsoB+lywdYQoiDyJBxP8dne7qs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Sng0UQHR; 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="Sng0UQHR" Received: by smtp.kernel.org (Postfix) with ESMTPS id 5FACEC4AF0B for ; Fri, 16 Aug 2024 07:43:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723794189; bh=l3JZvIn/HnfiPn+23+JJ+7h32og1cXxHlFtmiqQph+w=; h=From:To:Subject:Date:From; b=Sng0UQHRT4bXSAEwD+TOueoQEy3BEC45Euc7kRVMcAAiKG37975GMiJNjX/mt+53D J4FYfQcJpb+OAxNrfkmodpULsyQqmcU6smUCCedbJx7IcBUvqg+1cc2bdD8KQGFgL1 sH49H0swMq1xeinru6INAebLqa5Hd7nHruu7Hmv1XxNoAbjSw5+2EUHyEJIx5MQDxg 1EOe3LqcGHqvn6ShQ8B0my5H0xU7qd4X1FCDat+nfYxjBuwdY3ToJqssAq5vK5xBVN NvP2TatFbuc6Ac7I4DTfPK/sFn33Szd7dxqbbwzHId2wFammeZ9Or0+J0TVdMPVLT7 p9HFCNmGrJDkg== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 5244DC53B50; Fri, 16 Aug 2024 07:43:09 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-ext4@vger.kernel.org Subject: [Bug 219166] New: ext4 hang when setting echo noop > /sys/block/sda/queue/scheduler Date: Fri, 16 Aug 2024 07:43:09 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Product: File System X-Bugzilla-Component: ext4 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rjones@redhat.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter cf_regression Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D219166 Bug ID: 219166 Summary: ext4 hang when setting echo noop > /sys/block/sda/queue/scheduler Product: File System Version: 2.5 Hardware: All OS: Linux Status: NEW Severity: normal Priority: P3 Component: ext4 Assignee: fs_ext4@kernel-bugs.osdl.org Reporter: rjones@redhat.com Regression: No kernel-6.11.0-0.rc3.30.fc41.x86_64 This hang seems new in 6.11.0. Downstream bug: https://bugzilla.redhat.com/show_bug.cgi?id=3D2303267 Trying to change the queue/scheduler for a device containing an ext4 filesy= stem very rarely causes other processes which are using the filesystem to hang. This is running inside qemu. Using 'crash' I was able to get a stack trace from a couple of hanging processes (from different VM instances): crash> set 230 PID: 230 COMMAND: "modprobe" TASK: ffff98ce03ca3040 [THREAD_INFO: ffff98ce03ca3040] CPU: 0 STATE: TASK_UNINTERRUPTIBLE=20 crash> bt PID: 230 TASK: ffff98ce03ca3040 CPU: 0 COMMAND: "modprobe" #0 [ffffaf9940307840] __schedule at ffffffff9618f6d0 #1 [ffffaf99403078f8] schedule at ffffffff96190a27 #2 [ffffaf9940307908] __bio_queue_enter at ffffffff957e121c #3 [ffffaf9940307968] blk_mq_submit_bio at ffffffff957f358c #4 [ffffaf99403079f0] __submit_bio at ffffffff957e1e3c #5 [ffffaf9940307a58] submit_bio_noacct_nocheck at ffffffff957e2326 #6 [ffffaf9940307ac0] ext4_mpage_readpages at ffffffff955ceafc #7 [ffffaf9940307be0] read_pages at ffffffff95381d1a #8 [ffffaf9940307c40] page_cache_ra_unbounded at ffffffff95381ff5 #9 [ffffaf9940307ca8] filemap_fault at ffffffff953761b5 #10 [ffffaf9940307d48] __do_fault at ffffffff953d1895 #11 [ffffaf9940307d70] do_fault at ffffffff953d2425 #12 [ffffaf9940307da0] __handle_mm_fault at ffffffff953d8c6b #13 [ffffaf9940307e88] handle_mm_fault at ffffffff953d95c2 #14 [ffffaf9940307ec8] do_user_addr_fault at ffffffff950b34ea #15 [ffffaf9940307f28] exc_page_fault at ffffffff96186e4e #16 [ffffaf9940307f50] asm_exc_page_fault at ffffffff962012a6 RIP: 0000556b7a7468d8 RSP: 00007ffde2ffb560 RFLAGS: 00000206 RAX: 00000000000bec82 RBX: 00007f5331a0dc82 RCX: 0000556b7a75b92a RDX: 00007ffde2ffd8d0 RSI: 00000000200bec82 RDI: 0000556ba8edf960 RBP: 00007ffde2ffb7c0 R8: 0000000000000000 R9: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000200bec82 R13: 0000556ba8edf960 R14: 00007ffde2ffd8d0 R15: 0000556b7a760708 ORIG_RAX: ffffffffffffffff CS: 0033 SS: 002b crash> set 234 PID: 234 COMMAND: "modprobe" TASK: ffff9f5ec3a22f40 [THREAD_INFO: ffff9f5ec3a22f40] CPU: 0 STATE: TASK_UNINTERRUPTIBLE=20 crash> bt PID: 234 TASK: ffff9f5ec3a22f40 CPU: 0 COMMAND: "modprobe" #0 [ffffb21e002e7840] __schedule at ffffffffa718f6d0 #1 [ffffb21e002e78f8] schedule at ffffffffa7190a27 #2 [ffffb21e002e7908] __bio_queue_enter at ffffffffa67e121c #3 [ffffb21e002e7968] blk_mq_submit_bio at ffffffffa67f358c #4 [ffffb21e002e79f0] __submit_bio at ffffffffa67e1e3c #5 [ffffb21e002e7a58] submit_bio_noacct_nocheck at ffffffffa67e2326 #6 [ffffb21e002e7ac0] ext4_mpage_readpages at ffffffffa65ceafc #7 [ffffb21e002e7be0] read_pages at ffffffffa6381d17 #8 [ffffb21e002e7c40] page_cache_ra_unbounded at ffffffffa6381ff5 #9 [ffffb21e002e7ca8] filemap_fault at ffffffffa63761b5 #10 [ffffb21e002e7d48] __do_fault at ffffffffa63d1892 #11 [ffffb21e002e7d70] do_fault at ffffffffa63d2425 #12 [ffffb21e002e7da0] __handle_mm_fault at ffffffffa63d8c6b #13 [ffffb21e002e7e88] handle_mm_fault at ffffffffa63d95c2 #14 [ffffb21e002e7ec8] do_user_addr_fault at ffffffffa60b34ea #15 [ffffb21e002e7f28] exc_page_fault at ffffffffa7186e4e #16 [ffffb21e002e7f50] asm_exc_page_fault at ffffffffa72012a6 RIP: 000055d16159f8d8 RSP: 00007ffdd4c1f340 RFLAGS: 00010206 RAX: 00000000000bec82 RBX: 00007ff2fd00dc82 RCX: 000055d1615b492a RDX: 00007ffdd4c216b0 RSI: 00000000200bec82 RDI: 000055d185725960 RBP: 00007ffdd4c1f5a0 R8: 0000000000000000 R9: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000200bec82 R13: 000055d185725960 R14: 00007ffdd4c216b0 R15: 000055d1615b9708 ORIG_RAX: ffffffffffffffff CS: 0033 SS: 002b The hanging process was modprobe both times. I don't know if that is significant. Note that "noop" is not actually a valid scheduler (for about 10 years)! We still observe this hang even when setting it to this impossible value. # echo noop > /sys/block/sda/queue/scheduler /init: line 108: echo: write error: Invalid argument --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=