Hello, syzbot found the following issue on: HEAD commit: 7fa366f1b6e3 Add linux-next specific files for 20241218 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=14bbc2df980000 kernel config: https://syzkaller.appspot.com/x/.config?x=26a4b4cc7f877b28 dashboard link: https://syzkaller.appspot.com/bug?extid=eedb611600ae59683656 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=16cd6f44580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12bbc2df980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/76406ccde331/disk-7fa366f1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/49c56a285987/vmlinux-7fa366f1.xz kernel image: https://storage.googleapis.com/syzbot-assets/92d20cf0cd8a/bzImage-7fa366f1.xz The issue was bisected to: commit 032377449a80095d3526d263414fa7216bac5b2a Author: Suren Baghdasaryan <surenb@xxxxxxxxxx> Date: Mon Dec 16 19:24:13 2024 +0000 mm: replace vm_lock and detached flag with a reference count bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1078a2df980000 final oops: https://syzkaller.appspot.com/x/report.txt?x=1278a2df980000 console output: https://syzkaller.appspot.com/x/log.txt?x=1478a2df980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+eedb611600ae59683656@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 032377449a80 ("mm: replace vm_lock and detached flag with a reference count") ============================================ WARNING: possible recursive locking detected 6.13.0-rc3-next-20241218-syzkaller #0 Not tainted -------------------------------------------- syz-executor591/5830 is trying to acquire lock: ffff8880122abc08 (vm_lock){++++}-{0:0}, at: uffd_move_lock mm/userfaultfd.c:1477 [inline] ffff8880122abc08 (vm_lock){++++}-{0:0}, at: move_pages+0x26b/0x1680 mm/userfaultfd.c:1632 but task is already holding lock: ffff88823bfcafc8 (vm_lock){++++}-{0:0}, at: vma_start_read_locked include/linux/mm.h:803 [inline] ffff88823bfcafc8 (vm_lock){++++}-{0:0}, at: uffd_lock_vma+0x20c/0x2c0 mm/userfaultfd.c:88 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(vm_lock); lock(vm_lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor591/5830: #0: ffff88823bfcafc8 (vm_lock){++++}-{0:0}, at: vma_start_read_locked include/linux/mm.h:803 [inline] #0: ffff88823bfcafc8 (vm_lock){++++}-{0:0}, at: uffd_lock_vma+0x20c/0x2c0 mm/userfaultfd.c:88 #1: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: lock_vma_under_rcu+0x1dd/0xa40 mm/memory.c:6422 stack backtrace: CPU: 0 UID: 0 PID: 5830 Comm: syz-executor591 Not tainted 6.13.0-rc3-next-20241218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 vma_start_read include/linux/mm.h:744 [inline] lock_vma_under_rcu+0x370/0xa40 mm/memory.c:6427 uffd_move_lock mm/userfaultfd.c:1477 [inline] move_pages+0x26b/0x1680 mm/userfaultfd.c:1632 userfaultfd_move fs/userfaultfd.c:1899 [inline] userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff238379329 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffca8233748 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffca8233918 RCX: 00007ff238379329 RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003 RBP: 00007 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
