RE: [syzbot] [squashfs?] VFS: Close: file count is zero (use-after-free)

Kasireddy, Vivek
2024-06-13T06:23:04Z

> syzbot found the following issue on:
>
> HEAD commit: 0e1980c40b6e Add linux-next specific files for 20240531
> git tree: linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=13ac4616980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d9c3ca4e54577b88
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=b2cfdac9ae5278d4b621
> 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=17f01564980000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14484aba980000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-
> assets/44fb1d8b5978/disk-0e1980c4.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-
> assets/a66ce5caf0b2/vmlinux-0e1980c4.xz
> kernel image: https://storage.googleapis.com/syzbot-
> assets/8992fc8fe046/bzImage-0e1980c4.xz
> mounted in repro: https://storage.googleapis.com/syzbot-
> assets/8530480d64fb/mount_0.gz
>
> The issue was bisected to:
>
> commit 344a1d8575b05298d0702a9f9231e57db86a855e
> Author: Vivek Kasireddy <vivek.kasireddy@intel.com>
> Date: Thu Apr 11 06:59:42 2024 +0000
>
> udmabuf: convert udmabuf driver to use folios
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=153a7026980000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=173a7026980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=133a7026980000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b2cfdac9ae5278d4b621@syzkaller.appspotmail.com
> Fixes: 344a1d8575b0 ("udmabuf: convert udmabuf driver to use folios")
>
> VFS: Close: file count is 0 (f_op=shmem_file_operations)
> ------------[ cut here ]------------
> kernel BUG at fs/open.c:1514!
> Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
> CPU: 1 PID: 5089 Comm: syz-executor317 Not tainted 6.10.0-rc1-next-
> 20240531-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine,
> BIOS Google 04/02/2024
> RIP: 0010:filp_flush+0x152/0x160 fs/open.c:1512
> Code: e9 80 e1 07 80 c1 03 38 c1 7c a6 48 89 ef e8 c5 03 f0 ff eb 9c e8 6e 16 8a
> ff 48 c7 c7 20 59 d8 8b 48 89 ee e8 6f 84 7d 09 90 <0f> 0b 66 2e 0f 1f 84 00 00
> 00 00 00 66 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffc900033bfc80 EFLAGS: 00010246
> RAX: 0000000000000038 RBX: 0000000000000000 RCX: fe0d96255f7cdc00
> RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
> RBP: ffffffff8bd42dc0 R08: ffffffff8176b129 R09: 1ffff92000677f2c
> R10: dffffc0000000000 R11: fffff52000677f2d R12: ffff8880784d9680
> R13: dffffc0000000000 R14: ffff88807aa761c0 R15: 0000000000000009
> FS: 0000000000000000(0000) GS:ffff8880b9500000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000003f3be538 CR3: 000000007f062000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> filp_close+0x1e/0x40 fs/open.c:1532
> close_files fs/file.c:437 [inline]
> put_files_struct+0x1b6/0x360 fs/file.c:452
> do_exit+0xa08/0x28e0 kernel/exit.c:869
> do_group_exit+0x207/0x2c0 kernel/exit.c:1023
> __do_sys_exit_group kernel/exit.c:1034 [inline]
> __se_sys_exit_group kernel/exit.c:1032 [inline]
> __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
> x64_sys_call+0x26a8/0x26b0
> arch/x86/include/generated/asm/syscalls_64.h:232
> 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: 0033:0x7fc324e0fd09
> Code: Unable to access opcode bytes at 0x7fc324e0fcdf.
> RSP: 002b:00007fffe9a711b8 EFLAGS: 00000246 ORIG_RAX:
> 00000000000000e7
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc324e0fd09
> RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> RBP: 00007fc324e8b2d0 R08: ffffffffffffffb8 R09: 0000555580c204c0
> R10: 0000555580c204c0 R11: 0000000000000246 R12: 00007fc324e8b2d0
> R13: 0000000000000000 R14: 00007fc324e8c040 R15: 00007fc324dddf00
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:filp_flush+0x152/0x160 fs/open.c:1512
> Code: e9 80 e1 07 80 c1 03 38 c1 7c a6 48 89 ef e8 c5 03 f0 ff eb 9c e8 6e 16 8a
> ff 48 c7 c7 20 59 d8 8b 48 89 ee e8 6f 84 7d 09 90 <0f> 0b 66 2e 0f 1f 84 00 00
> 00 00 00 66 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffc900033bfc80 EFLAGS: 00010246
> RAX: 0000000000000038 RBX: 0000000000000000 RCX: fe0d96255f7cdc00
> RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
> RBP: ffffffff8bd42dc0 R08: ffffffff8176b129 R09: 1ffff92000677f2c
> R10: dffffc0000000000 R11: fffff52000677f2d R12: ffff8880784d9680
> R13: dffffc0000000000 R14: ffff88807aa761c0 R15: 0000000000000009
> FS: 0000000000000000(0000) GS:ffff8880b9500000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000003f3be538 CR3: 000000007f062000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This report is generated by a bot. It may contain errors.
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>
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>
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>
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#syz test: https://gitlab.freedesktop.org/Vivek/drm-tip.git syzbot_fixes