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X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a02309c.170a0220.7f9b3.0000.GAE@google.com> Subject: [moderation/CI] Re: fs: Fix missed inode write during fsync From: syzbot ci To: syzkaller-upstream-moderation@googlegroups.com Cc: syzbot@lists.linux.dev Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v1] fs: Fix missed inode write during fsync https://lore.kernel.org/all/20260511115725.28441-1-jack@suse.cz * [PATCH 1/9] affs: Drop support for metadata bh tracking * [PATCH 2/9] ext4: Allocate mapping_metadata_bhs struct on demand * [PATCH 3/9] fs: Writeout inode buffer from mmb_sync() * [PATCH 4/9] ext2: Fix possibly missing inode write on fsync(2) * [PATCH 5/9] udf: Fix possibly missing inode write on fsync(2) * [PATCH 6/9] fat: Fix possibly missing inode write on fsync(2) * [PATCH 7/9] minix: Fix possibly missing inode write on fsync(2) * [PATCH 8/9] bfs: Fix possibly missing inode write on fsync(2) * [PATCH 9/9] ext4: Use mmb infrastructure for inode buffer writeout and found the following issue: KASAN: null-ptr-deref Write in write_dirty_buffer Full report is available here: https://ci.syzbot.org/series/d987d2d8-3775-4aa9-959f-8a045778888c *** KASAN: null-ptr-deref Write in write_dirty_buffer tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 5d6919055dec134de3c40167a490f33c74c12581 arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/567d596c-ca65-43c9-bd7d-1e60cfe9da2a/config syz repro: https://ci.syzbot.org/findings/1bc13af8-2d91-4fbd-b43e-fbe72f29ca41/syz_repro EXT4-fs (loop2): unmounting filesystem 00000000-0000-0000-0000-000000000000. ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: null-ptr-deref in test_and_set_bit_lock include/asm-generic/bitops/instrumented-lock.h:57 [inline] BUG: KASAN: null-ptr-deref in trylock_buffer include/linux/buffer_head.h:425 [inline] BUG: KASAN: null-ptr-deref in lock_buffer include/linux/buffer_head.h:431 [inline] BUG: KASAN: null-ptr-deref in write_dirty_buffer+0x37/0x190 fs/buffer.c:2760 Write of size 8 at addr 0000000000000000 by task syz-executor/5742 CPU: 1 UID: 0 PID: 5742 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] test_and_set_bit_lock include/asm-generic/bitops/instrumented-lock.h:57 [inline] trylock_buffer include/linux/buffer_head.h:425 [inline] lock_buffer include/linux/buffer_head.h:431 [inline] write_dirty_buffer+0x37/0x190 fs/buffer.c:2760 mmb_sync+0x74c/0xed0 fs/buffer.c:603 ext4_evict_inode+0x2fa/0x1040 fs/ext4/inode.c:199 evict+0x61e/0xb10 fs/inode.c:841 ext4_quota_off+0x470/0x580 fs/ext4/super.c:7326 ext4_quotas_off fs/ext4/super.c:1195 [inline] ext4_put_super+0xdf/0xd80 fs/ext4/super.c:1306 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646 kill_block_super+0x44/0x90 fs/super.c:1725 ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7494 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd8d1b9e017 Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffef04ebf88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fd8d1c32120 RCX: 00007fd8d1b9e017 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffef04ec040 RBP: 00007ffef04ec040 R08: 00007ffef04ed040 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffef04ed0d0 R13: 00007fd8d1c32120 R14: 0000000000014595 R15: 00007ffef04ed110 ================================================================== *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. To test a patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported. The email will later be sent to: [aivazian.tigran@gmail.com brauner@kernel.org dsterba@suse.com hirofumi@mail.parknet.co.jp jack@suse.cz linux-ext4@vger.kernel.org linux-fsdevel@vger.kernel.org tytso@mit.edu] If the report looks fine to you, reply with: #syz upstream If the report is a false positive, reply with #syz invalid