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006d021491bc7-67e10ce7d8dmr3355794eaf.20.1774703786513; Sat, 28 Mar 2026 06:16:26 -0700 (PDT) Date: Sat, 28 Mar 2026 06:16:26 -0700 In-Reply-To: <69bdce08.050a0220.3bf4de.0031.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69c7d4aa.a70a0220.128fd0.0027.GAE@google.com> Subject: Re: [syzbot] [fs?] general protection fault in __umount_mnt From: syzbot To: brauner@kernel.org, jack@suse.cz, kartikey406@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com, raven@themaw.net, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 3b058d1aeeef Add linux-next specific files for 20260327 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=11bd16f6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4acce231a75c746f dashboard link: https://syzkaller.appspot.com/bug?extid=e4470cc28308f2081ec8 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11dc6606580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15baca26580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/5a5b73363d45/disk-3b058d1a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ecba5c3ac106/vmlinux-3b058d1a.xz kernel image: https://storage.googleapis.com/syzbot-assets/348124eb71de/bzImage-3b058d1a.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e4470cc28308f2081ec8@syzkaller.appspotmail.com Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN PTI KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] CPU: 0 UID: 0 PID: 6113 Comm: syz.0.28 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__hlist_del include/linux/list.h:992 [inline] RIP: 0010:hlist_del_init include/linux/list.h:1020 [inline] RIP: 0010:__umount_mnt+0x24e/0x490 fs/namespace.c:997 Code: 85 e4 74 61 4d 8d be f8 00 00 00 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 ac 3f e3 ff 4d 8b 2f 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 84 40 e3 ff 4d 89 2c 24 4d 85 ed 74 RSP: 0018:ffffc900033a7a20 EFLAGS: 00010a06 RAX: 1bd5a00000000024 RBX: ffff88807dcb5188 RCX: ffff88803244bd00 RDX: 0000000000000000 RSI: ffffffff8e8d83a0 RDI: ffff88807dcb51f8 RBP: dffffc0000000000 R08: ffffffff90128af7 R09: 1ffffffff202515e R10: dffffc0000000000 R11: fffffbfff202515f R12: dead000000000122 R13: dead000000000100 R14: ffff88807dcb5180 R15: ffff88807dcb5278 FS: 000055558d53f500(0000) GS:ffff88812543f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50a85ea078 CR3: 0000000076400000 CR4: 00000000003526f0 Call Trace: umount_mnt fs/namespace.c:1008 [inline] umount_tree+0x925/0xd90 fs/namespace.c:1819 put_mnt_ns+0x1d6/0x2f0 fs/namespace.c:6264 evict+0x61e/0xb10 fs/inode.c:846 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670 finish_dput+0xc9/0x480 fs/dcache.c:879 __fput+0x691/0xa70 fs/file_table.c:477 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f265d99c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe16be4ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f265dc17da0 RCX: 00007f265d99c799 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f265dc17da0 R08: 00007f265dc16038 R09: 0000000000000000 R10: 000000000003fda8 R11: 0000000000000246 R12: 00000000000161c9 R13: 00007f265dc1609c R14: 0000000000015fb1 R15: 00007f265dc16090 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__hlist_del include/linux/list.h:992 [inline] RIP: 0010:hlist_del_init include/linux/list.h:1020 [inline] RIP: 0010:__umount_mnt+0x24e/0x490 fs/namespace.c:997 Code: 85 e4 74 61 4d 8d be f8 00 00 00 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 ac 3f e3 ff 4d 8b 2f 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 84 40 e3 ff 4d 89 2c 24 4d 85 ed 74 RSP: 0018:ffffc900033a7a20 EFLAGS: 00010a06 RAX: 1bd5a00000000024 RBX: ffff88807dcb5188 RCX: ffff88803244bd00 RDX: 0000000000000000 RSI: ffffffff8e8d83a0 RDI: ffff88807dcb51f8 RBP: dffffc0000000000 R08: ffffffff90128af7 R09: 1ffffffff202515e R10: dffffc0000000000 R11: fffffbfff202515f R12: dead000000000122 R13: dead000000000100 R14: ffff88807dcb5180 R15: ffff88807dcb5278 FS: 000055558d53f500(0000) GS:ffff88812543f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50a85ea078 CR3: 0000000076400000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: 85 e4 test %esp,%esp 2: 74 61 je 0x65 4: 4d 8d be f8 00 00 00 lea 0xf8(%r14),%r15 b: 4c 89 f8 mov %r15,%rax e: 48 c1 e8 03 shr $0x3,%rax 12: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) 16: 74 08 je 0x20 18: 4c 89 ff mov %r15,%rdi 1b: e8 ac 3f e3 ff call 0xffe33fcc 20: 4d 8b 2f mov (%r15),%r13 23: 4c 89 e0 mov %r12,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 e7 mov %r12,%rdi 33: e8 84 40 e3 ff call 0xffe340bc 38: 4d 89 2c 24 mov %r13,(%r12) 3c: 4d 85 ed test %r13,%r13 3f: 74 .byte 0x74 --- 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.