syzbot has found a reproducer for the following issue on: HEAD commit: 87a132e73910 Merge tag 'mm-hotfixes-stable-2025-02-19-17-4.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=175775b0580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1 dashboard link: https://syzkaller.appspot.com/bug?extid=e733ab672a1b6724c27f 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=16d8aba4580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11e1dae4580000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4a88f50cb21d/disk-87a132e7.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d970e0210e8a/vmlinux-87a132e7.xz kernel image: https://storage.googleapis.com/syzbot-assets/9b6329058ef7/bzImage-87a132e7.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/f06af6381842/mount_0.gz The issue was bisected to: commit d97de0d017cde0d442c3d144b4f969f43064cc0f Author: Kent Overstreet <[email protected]> Date: Tue Aug 13 01:31:25 2024 +0000 bcachefs: Make bkey_fsck_err() a wrapper around fsck_err() bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13432ef8580000 final oops: https://syzkaller.appspot.com/x/report.txt?x=10c32ef8580000 console output: https://syzkaller.appspot.com/x/log.txt?x=17432ef8580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: [email protected] Fixes: d97de0d017cd ("bcachefs: Make bkey_fsck_err() a wrapper around fsck_err()") ------------[ cut here ]------------ ================================================================== BUG: KASAN: global-out-of-bounds in string_nocheck lib/vsprintf.c:632 [inline] BUG: KASAN: global-out-of-bounds in string+0x229/0x2b0 lib/vsprintf.c:714 Read of size 1 at addr ffffffff8c74c10a by task syz-executor504/5826 CPU: 1 UID: 0 PID: 5826 Comm: syz-executor504 Not tainted 6.14.0-rc3-syzkaller-00079-g87a132e73910 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x16e/0x5b0 mm/kasan/report.c:521 kasan_report+0x143/0x180 mm/kasan/report.c:634 string_nocheck lib/vsprintf.c:632 [inline] string+0x229/0x2b0 lib/vsprintf.c:714 vsnprintf+0x8b4/0x1220 lib/vsprintf.c:2843 vprintk_store+0x482/0x1240 kernel/printk/printk.c:2279 vprintk_emit+0x271/0xa10 kernel/printk/printk.c:2408 __warn_printk+0x263/0x360 kernel/panic.c:797 look_up_lock_class+0xdb/0x170 kernel/locking/lockdep.c:938 register_lock_class+0x102/0x980 kernel/locking/lockdep.c:1292 __lock_acquire+0xf3/0x2100 kernel/locking/lockdep.c:5103 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] rcu_pending_has_pending_or_armed fs/bcachefs/rcu_pending.c:592 [inline] rcu_pending_exit+0x13f/0x7a0 fs/bcachefs/rcu_pending.c:610 bch2_fs_btree_key_cache_exit+0x8d1/0x9f0 fs/bcachefs/btree_key_cache.c:778 __bch2_fs_free fs/bcachefs/super.c:569 [inline] bch2_fs_release+0x206/0x7b0 fs/bcachefs/super.c:624 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x231/0x480 lib/kobject.c:737 deactivate_locked_super+0xc6/0x130 fs/super.c:473 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1413 task_work_run+0x251/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7e807c2577 Code: 07 00 48 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffeee02cd28 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f7e807c2577 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeee02cde0 RBP: 00007ffeee02cde0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000206 R12: 00007ffeee02de50 R13: 000055557adeb6c0 R14: 431bde82d7b634db R15: 00007ffeee02de70 </TASK> The buggy address belongs to the variable: .str+0xa/0x20 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xc74c flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000002000 ffffea000031d308 ffffea000031d308 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffffffff8c74c000: 00 05 f9 f9 02 f9 f9 f9 06 f9 f9 f9 00 00 00 00 ffffffff8c74c080: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00 >ffffffff8c74c100: 00 01 f9 f9 00 00 00 04 f9 f9 f9 f9 00 00 00 00 ^ ffffffff8c74c180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffff8c74c200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
