Hello, syzbot found the following issue on: HEAD commit: a5541c0811a0 Merge branch 'for-next/core' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=1310cd10480000 kernel config: https://syzkaller.appspot.com/x/.config?x=cbd4e584773e9397 dashboard link: https://syzkaller.appspot.com/bug?extid=ac031e7435393ad05df6 compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: arm64 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=151fd1f0480000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122eacc8480000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4b7702208fb9/disk-a5541c08.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9ec0153ec051/vmlinux-a5541c08.xz kernel image: https://storage.googleapis.com/syzbot-assets/6f8725ad290a/Image-a5541c08.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ac031e7435393ad05df6@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 3448 at lib/refcount.c:28 refcount_warn_saturate+0x1a0/0x1c8 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 3448 Comm: syz-executor242 Not tainted 6.1.0-rc8-syzkaller-33330-ga5541c0811a0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x1a0/0x1c8 lib/refcount.c:28 lr : refcount_warn_saturate+0x1a0/0x1c8 lib/refcount.c:28 sp : ffff800012ed3c60 x29: ffff800012ed3c60 x28: ffff80000c40fe48 x27: 0000000000000006 x26: ffff0000c70d6508 x25: 0000000000000000 x24: ffff0000c70d6400 x23: 0000000000000000 x22: ffff80000f183000 x21: 0000000000000000 x20: 0000000000000003 x19: ffff80000d95e000 x18: 000000000000030d x17: ffff80000c0cd83c x16: ffff80000dbe6158 x15: ffff0000cdd34ec0 x14: 0000000000000000 x13: 00000000ffffffff x12: ffff0000cdd34ec0 x11: ff808000081c4d64 x10: 0000000000000000 x9 : 6a9cd14bd183ed00 x8 : 6a9cd14bd183ed00 x7 : ffff80000816678c x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000 x2 : 0000000000000006 x1 : 0000000100000000 x0 : 0000000000000026 Call trace: refcount_warn_saturate+0x1a0/0x1c8 lib/refcount.c:28 __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] gadgetfs_kill_sb+0xd4/0x104 drivers/usb/gadget/legacy/inode.c:2086 deactivate_locked_super+0x70/0xe8 fs/super.c:332 vfs_get_super fs/super.c:1190 [inline] get_tree_single+0x98/0xe8 fs/super.c:1207 gadgetfs_get_tree+0x28/0x38 drivers/usb/gadget/legacy/inode.c:2068 vfs_get_tree+0x40/0x140 fs/super.c:1531 vfs_fsconfig_locked fs/fsopen.c:232 [inline] __do_sys_fsconfig fs/fsopen.c:439 [inline] __se_sys_fsconfig fs/fsopen.c:314 [inline] __arm64_sys_fsconfig+0x758/0x818 fs/fsopen.c:314 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 irq event stamp: 442 hardirqs last enabled at (441): [<ffff80000816681c>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1366 [inline] hardirqs last enabled at (441): [<ffff80000816681c>] finish_lock_switch+0x94/0xe8 kernel/sched/core.c:4968 hardirqs last disabled at (442): [<ffff80000c084084>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (360): [<ffff80000801c82c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (358): [<ffff80000801c7f8>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- --- 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. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
