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 75AB2679F8; Thu, 8 Feb 2024 05:21:32 +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=1707369692; cv=none; b=jqHfYnD0PUrsP83uUHKOwnpMp9aRFanvTTTn7uRSa8otp55jhPSeRMYOmMq9y7CsQHiIWBO6vfTiXojmaEdjQKm5QNrDFGvqs4zeScFzJTEvShTSfEmOkhvD+DhjnVHNxTsN/+meemmfz9hNWqL4yhdljD2H+Tti2e+ocK1msTk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707369692; c=relaxed/simple; bh=77P7cbLLsnqfGsV8SeR/2Gyh23p3Yl6T1HmLy7WUSSA=; h=Date:To:From:Subject:Message-Id; b=UPvKQXBG3SIRcYH1HqYHUUcAcONjJ9nr2kGgb2czos9Y/VgAzVq8Y5nLe1wNaP2bAAm8f3S/XQBjkMPlvM1Buts+2A6wGaREk9oxjS+fyaGHkqWFWBcvH8xlaa6qrnHp5JSO2z8N6dha1qS/cckp0EqSeLS7kf6VFwFh+lfZA3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ictLoP+o; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ictLoP+o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00A05C433C7; Thu, 8 Feb 2024 05:21:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1707369692; bh=77P7cbLLsnqfGsV8SeR/2Gyh23p3Yl6T1HmLy7WUSSA=; h=Date:To:From:Subject:From; b=ictLoP+odKUCJJ2MqeACNqgAwJplPCtUAfpcWLvsOnjazTPfsXsugnKbQZ9ewN09b 0RO7l/anOynA+grUrLU2YUtHkwpfp0pbvdqHeZNTymlozdKg9vycLTe/pyW59CbaWq GZVZkxM6FCq0daFBYtdq8uacKPCTjJfayheeX/+8= Date: Wed, 07 Feb 2024 21:21:31 -0800 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,konishi.ryusuke@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] nilfs2-fix-potential-bug-in-end_buffer_async_write.patch removed from -mm tree Message-Id: <20240208052132.00A05C433C7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: nilfs2: fix potential bug in end_buffer_async_write has been removed from the -mm tree. Its filename was nilfs2-fix-potential-bug-in-end_buffer_async_write.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ryusuke Konishi Subject: nilfs2: fix potential bug in end_buffer_async_write Date: Sun, 4 Feb 2024 01:16:45 +0900 According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2. Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash. This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel. The use of async_write for segment summary buffers has already been removed in a previous change. Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer. Link: https://lkml.kernel.org/r/20240203161645.4992-1-konishi.ryusuke@gmail.com Fixes: 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") Signed-off-by: Ryusuke Konishi Reported-by: syzbot+5c04210f7c7f897c1e7f@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/00000000000019a97c05fd42f8c8@google.com Cc: Signed-off-by: Andrew Morton --- fs/nilfs2/segment.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/fs/nilfs2/segment.c~nilfs2-fix-potential-bug-in-end_buffer_async_write +++ a/fs/nilfs2/segment.c @@ -1703,7 +1703,6 @@ static void nilfs_segctor_prepare_write( list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { - set_buffer_async_write(bh); if (bh == segbuf->sb_super_root) { if (bh->b_folio != bd_folio) { folio_lock(bd_folio); @@ -1714,6 +1713,7 @@ static void nilfs_segctor_prepare_write( } break; } + set_buffer_async_write(bh); if (bh->b_folio != fs_folio) { nilfs_begin_folio_io(fs_folio); fs_folio = bh->b_folio; @@ -1800,7 +1800,6 @@ static void nilfs_abort_logs(struct list list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { - clear_buffer_async_write(bh); if (bh == segbuf->sb_super_root) { clear_buffer_uptodate(bh); if (bh->b_folio != bd_folio) { @@ -1809,6 +1808,7 @@ static void nilfs_abort_logs(struct list } break; } + clear_buffer_async_write(bh); if (bh->b_folio != fs_folio) { nilfs_end_folio_io(fs_folio, err); fs_folio = bh->b_folio; @@ -1896,8 +1896,9 @@ static void nilfs_segctor_complete_write BIT(BH_Delay) | BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Redirected)); - set_mask_bits(&bh->b_state, clear_bits, set_bits); if (bh == segbuf->sb_super_root) { + set_buffer_uptodate(bh); + clear_buffer_dirty(bh); if (bh->b_folio != bd_folio) { folio_end_writeback(bd_folio); bd_folio = bh->b_folio; @@ -1905,6 +1906,7 @@ static void nilfs_segctor_complete_write update_sr = true; break; } + set_mask_bits(&bh->b_state, clear_bits, set_bits); if (bh->b_folio != fs_folio) { nilfs_end_folio_io(fs_folio, 0); fs_folio = bh->b_folio; _ Patches currently in -mm which might be from konishi.ryusuke@gmail.com are nilfs2-convert-segment-buffer-to-use-kmap_local.patch nilfs2-convert-nilfs_copy_buffer-to-use-kmap_local.patch nilfs2-convert-metadata-file-common-code-to-use-kmap_local.patch nilfs2-convert-sufile-to-use-kmap_local.patch nilfs2-convert-persistent-object-allocator-to-use-kmap_local.patch nilfs2-convert-dat-to-use-kmap_local.patch nilfs2-move-nilfs_bmap_write-call-out-of-nilfs_write_inode_common.patch nilfs2-do-not-acquire-rwsem-in-nilfs_bmap_write.patch nilfs2-convert-ifile-to-use-kmap_local.patch nilfs2-localize-highmem-mapping-for-checkpoint-creation-within-cpfile.patch nilfs2-localize-highmem-mapping-for-checkpoint-finalization-within-cpfile.patch nilfs2-localize-highmem-mapping-for-checkpoint-reading-within-cpfile.patch nilfs2-remove-nilfs_cpfile_getput_checkpoint.patch nilfs2-convert-cpfile-to-use-kmap_local.patch