Amir Goldstein <amir73il@xxxxxxxxx> writes: > On Thu, Apr 11, 2024 at 3:13 PM Jan Kara <jack@xxxxxxx> wrote: >> >> On Thu 11-04-24 01:11:20, syzbot wrote: >> > Hello, >> > >> > syzbot found the following issue on: >> > >> > HEAD commit: 6ebf211bb11d Add linux-next specific files for 20240410 >> > git tree: linux-next >> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12be955d180000 >> > kernel config: https://syzkaller.appspot.com/x/.config?x=16ca158ef7e08662 >> > dashboard link: https://syzkaller.appspot.com/bug?extid=5e3f9b2a67b45f16d4e6 >> > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 >> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c91175180000 >> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1621af9d180000 >> > >> > Downloadable assets: >> > disk image: https://storage.googleapis.com/syzbot-assets/b050f81f73ed/disk-6ebf211b.raw.xz >> > vmlinux: https://storage.googleapis.com/syzbot-assets/412c9b9a536e/vmlinux-6ebf211b.xz >> > kernel image: https://storage.googleapis.com/syzbot-assets/016527216c47/bzImage-6ebf211b.xz >> > mounted in repro: https://storage.googleapis.com/syzbot-assets/75ad050c9945/mount_0.gz >> > >> > IMPORTANT: if you fix the issue, please add the following tag to the commit: >> > Reported-by: syzbot+5e3f9b2a67b45f16d4e6@xxxxxxxxxxxxxxxxxxxxxxxxx >> > >> > Quota error (device loop0): do_check_range: Getting block 0 out of range 1-5 >> > EXT4-fs error (device loop0): ext4_release_dquot:6905: comm kworker/u8:4: Failed to release dquot type 1 >> > ================================================================== >> > BUG: KASAN: slab-use-after-free in fsnotify+0x2a4/0x1f70 fs/notify/fsnotify.c:539 >> > Read of size 8 at addr ffff88802f1dce80 by task kworker/u8:4/62 >> > >> > CPU: 0 PID: 62 Comm: kworker/u8:4 Not tainted 6.9.0-rc3-next-20240410-syzkaller #0 >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 >> > Workqueue: events_unbound quota_release_workfn >> > Call Trace: >> > <TASK> >> > __dump_stack lib/dump_stack.c:88 [inline] >> > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 >> > print_address_description mm/kasan/report.c:377 [inline] >> > print_report+0x169/0x550 mm/kasan/report.c:488 >> > kasan_report+0x143/0x180 mm/kasan/report.c:601 >> > fsnotify+0x2a4/0x1f70 fs/notify/fsnotify.c:539 >> > fsnotify_sb_error include/linux/fsnotify.h:456 [inline] >> > __ext4_error+0x255/0x3b0 fs/ext4/super.c:843 >> > ext4_release_dquot+0x326/0x450 fs/ext4/super.c:6903 >> > quota_release_workfn+0x39f/0x650 fs/quota/dquot.c:840 >> > process_one_work kernel/workqueue.c:3218 [inline] >> > process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3299 >> > worker_thread+0x86d/0xd70 kernel/workqueue.c:3380 >> > kthread+0x2f0/0x390 kernel/kthread.c:389 >> > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 >> > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 >> > </TASK> >> >> Amir, I believe this happens on umount when the filesystem calls >> fsnotify_sb_error() after calling fsnotify_sb_delete(). In theory these two >> calls can even run in parallel and fsnotify() can be holding >> fsnotify_sb_info pointer while fsnotify_sb_delete() is freeing it so we >> need to figure out some proper synchronization for that... > > Is it really needed to handle any for non SB_ACTIVE sb? I think it should be fine to exclude volumes being teared down. Cc'ing Khazhy, who sponsored this work at the time and owned the use-case. -- Gabriel Krisman Bertazi
