fs/super.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
get_tree_bdev_flags() hands fc->s_fs_info to the newly allocated
super block in sget_fc() and clears fc->s_fs_info. If
setup_bdev_super() then fails (the block device cannot be opened, is
read-only, or is frozen), fill_super() is never called and sb->s_root
stays NULL. The cleanup path calls deactivate_locked_super(), whose
generic_shutdown_super() skips the whole sb->s_root block -- including
the put_super() callback that would otherwise release s_fs_info --
leaking the allocation made by the filesystem's init_fs_context().
Hand s_fs_info back to the fs_context when setup_bdev_super() fails so
that put_fs_context() releases it through the filesystem's free()
callback.
Reported-by: syzbot+1c70732df5fd4f0e4fbb@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=1c70732df5fd4f0e4fbb
Signed-off-by: hanzhijian <hanzhijian1991@gmail.com>
---
fs/super.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/fs/super.c b/fs/super.c
index 05e443173..8b978b67b 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1883,8 +1883,19 @@ int get_tree_bdev_flags(struct fs_context *fc,
}
} else {
error = setup_bdev_super(s, fc->sb_flags, fc);
- if (!error)
- error = fill_super(s, fc);
+ if (error) {
+ /*
+ * fill_super() was not called, so nothing has taken
+ * ownership of fc->s_fs_info. Hand it back so that
+ * put_fs_context() can release it, otherwise it
+ * leaks.
+ */
+ fc->s_fs_info = s->s_fs_info;
+ s->s_fs_info = NULL;
+ deactivate_locked_super(s);
+ return error;
+ }
+ error = fill_super(s, fc);
if (error) {
deactivate_locked_super(s);
return error;
--
2.43.0On Sat, Aug 22, 2026 at 10:39:18AM +0800, hanzhijian wrote: > get_tree_bdev_flags() hands fc->s_fs_info to the newly allocated > super block in sget_fc() and clears fc->s_fs_info. If > setup_bdev_super() then fails (the block device cannot be opened, is > read-only, or is frozen), fill_super() is never called and sb->s_root > stays NULL. The cleanup path calls deactivate_locked_super(), whose > generic_shutdown_super() skips the whole sb->s_root block -- including > the put_super() callback that would otherwise release s_fs_info -- > leaking the allocation made by the filesystem's init_fs_context(). > > Hand s_fs_info back to the fs_context when setup_bdev_super() fails so > that put_fs_context() releases it through the filesystem's free() > callback. > > Reported-by: syzbot+1c70732df5fd4f0e4fbb@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=1c70732df5fd4f0e4fbb > Signed-off-by: hanzhijian <hanzhijian1991@gmail.com> > --- There's a fix for this in vfs.fixes. This is the wrong layer.
syzbot ci has tested the following series [v1] fs: fix s_fs_info leak when setup_bdev_super() fails https://lore.kernel.org/all/20260822023918.2498361-1-hanzhijian1991@gmail.com * [PATCH] fs: fix s_fs_info leak when setup_bdev_super() fails and found the following issues: * general protection fault in call_rcu * general protection fault in erofs_kill_sb * general protection fault in fuse_kill_sb_blk * general protection fault in xfs_kill_sb Full report is available here: https://ci.syzbot.org/series/1ef55243-f163-4d98-bbd1-41b579082704 *** general protection fault in call_rcu tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 26260251022fbc2f248a3d747a9b2b961b18d2d8 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/41c2a7e2-d41f-466f-8380-e05ef414bf62/config syz repro: https://ci.syzbot.org/findings/f6ebcbaf-d8f4-4c25-9e68-98f46740729d/syz_repro /dev/sr0: Can't open blockdev Oops: general protection fault, probably for non-canonical address 0xdffffc000000005a: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x00000000000002d0-0x00000000000002d7] CPU: 0 UID: 0 PID: 5792 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:__call_rcu_common kernel/rcu/tree.c:3157 [inline] RIP: 0010:call_rcu+0xb9/0x8b0 kernel/rcu/tree.c:3279 Code: 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 0e eb 8a 00 48 c7 03 c0 9a ac 81 e9 b3 05 00 00 48 8d 7b 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 eb ea 8a 00 4c 89 73 08 48 89 d8 48 c1 e8 RSP: 0018:ffffc900041dfb08 EFLAGS: 00010206 RAX: 000000000000005a RBX: 00000000000002c8 RCX: ffffffff9a9ab501 RDX: 0000000000000001 RSI: ffffffff8e46456f RDI: 00000000000002d0 RBP: 0000000000000000 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: fffffbfff20f27a7 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff82b4b6c0 R15: ffff88811e37e7a0 FS: 00007f1ef40546c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1ef4053ff8 CR3: 0000000173ace000 CR4: 00000000000006f0 Call Trace: <TASK> deactivate_locked_super+0xbc/0x110 fs/super.c:603 get_tree_bdev_flags+0x40e/0x560 fs/super.c:1895 vfs_get_tree+0x92/0x2a0 fs/super.c:1958 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3772 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3848 do_mount fs/namespace.c:4181 [inline] __do_sys_mount fs/namespace.c:4397 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4374 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1ef319e0d9 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:00007f1ef4054028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f1ef3425fa0 RCX: 00007f1ef319e0d9 RDX: 0000200000000080 RSI: 00002000000000c0 RDI: 0000200000000000 RBP: 00007f1ef3235024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000214003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1ef3426038 R14: 00007f1ef3425fa0 R15: 00007ffc4bde52a8 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__call_rcu_common kernel/rcu/tree.c:3157 [inline] RIP: 0010:call_rcu+0xb9/0x8b0 kernel/rcu/tree.c:3279 Code: 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 0e eb 8a 00 48 c7 03 c0 9a ac 81 e9 b3 05 00 00 48 8d 7b 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 eb ea 8a 00 4c 89 73 08 48 89 d8 48 c1 e8 RSP: 0018:ffffc900041dfb08 EFLAGS: 00010206 RAX: 000000000000005a RBX: 00000000000002c8 RCX: ffffffff9a9ab501 RDX: 0000000000000001 RSI: ffffffff8e46456f RDI: 00000000000002d0 RBP: 0000000000000000 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: fffffbfff20f27a7 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff82b4b6c0 R15: ffff88811e37e7a0 FS: 00007f1ef40546c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1ef4053ff8 CR3: 0000000173ace000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 48 c1 e8 03 shr $0x3,%rax 4: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) 9: 74 08 je 0x13 b: 48 89 df mov %rbx,%rdi e: e8 0e eb 8a 00 call 0x8aeb21 13: 48 c7 03 c0 9a ac 81 movq $0xffffffff81ac9ac0,(%rbx) 1a: e9 b3 05 00 00 jmp 0x5d2 1f: 48 8d 7b 08 lea 0x8(%rbx),%rdi 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 2f: 74 05 je 0x36 31: e8 eb ea 8a 00 call 0x8aeb21 36: 4c 89 73 08 mov %r14,0x8(%rbx) 3a: 48 89 d8 mov %rbx,%rax 3d: 48 rex.W 3e: c1 .byte 0xc1 3f: e8 .byte 0xe8 *** general protection fault in erofs_kill_sb tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 26260251022fbc2f248a3d747a9b2b961b18d2d8 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/41c2a7e2-d41f-466f-8380-e05ef414bf62/config syz repro: https://ci.syzbot.org/findings/a828baa5-9634-4255-a0b1-41e60df7067d/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 UID: 0 PID: 5846 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:erofs_kill_sb+0x53/0x270 fs/erofs/super.c:950 Code: 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 08 80 3c 28 00 74 08 48 89 df e8 bb 60 b8 fd 4c 8b 33 4d 8d 66 08 4d 89 e7 49 c1 ef 03 <41> 80 3c 2f 00 74 08 4c 89 e7 e8 9e 60 b8 fd 49 83 3c 24 00 4c 89 RSP: 0018:ffffc90003dbfc08 EFLAGS: 00010202 RAX: 1ffff1102edb18cf RBX: ffff888176d8c678 RCX: ffff88816bcabc00 RDX: 0000000000000000 RSI: ffffffff8e46456f RDI: ffff888176d8c000 RBP: dffffc0000000000 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: ffffffff847e7250 R12: 0000000000000008 R13: ffff888176d8c000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007efdff1c96c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff27edb9095 CR3: 0000000174554000 CR4: 00000000000006f0 Call Trace: <TASK> deactivate_locked_super+0xbc/0x110 fs/super.c:603 get_tree_bdev_flags+0x40e/0x560 fs/super.c:1895 vfs_get_tree+0x92/0x2a0 fs/super.c:1958 vfs_cmd_create+0xa2/0x200 fs/fsopen.c:231 __do_sys_fsconfig fs/fsopen.c:463 [inline] __se_sys_fsconfig+0x6b9/0x810 fs/fsopen.c:350 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efdfe39e0d9 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:00007efdff1c9028 EFLAGS: 00000246 ORIG_RAX: 00000000000001af RAX: ffffffffffffffda RBX: 00007efdfe625fa0 RCX: 00007efdfe39e0d9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 00007efdfe435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efdfe626038 R14: 00007efdfe625fa0 R15: 00007ffde183e908 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:erofs_kill_sb+0x53/0x270 fs/erofs/super.c:950 Code: 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 08 80 3c 28 00 74 08 48 89 df e8 bb 60 b8 fd 4c 8b 33 4d 8d 66 08 4d 89 e7 49 c1 ef 03 <41> 80 3c 2f 00 74 08 4c 89 e7 e8 9e 60 b8 fd 49 83 3c 24 00 4c 89 RSP: 0018:ffffc90003dbfc08 EFLAGS: 00010202 RAX: 1ffff1102edb18cf RBX: ffff888176d8c678 RCX: ffff88816bcabc00 RDX: 0000000000000000 RSI: ffffffff8e46456f RDI: ffff888176d8c000 RBP: dffffc0000000000 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: ffffffff847e7250 R12: 0000000000000008 R13: ffff888176d8c000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007efdff1c96c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff27edb9095 CR3: 0000000174554000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 89 d8 mov %rbx,%rax 5: 48 c1 e8 03 shr $0x3,%rax 9: 48 89 44 24 08 mov %rax,0x8(%rsp) e: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) 12: 74 08 je 0x1c 14: 48 89 df mov %rbx,%rdi 17: e8 bb 60 b8 fd call 0xfdb860d7 1c: 4c 8b 33 mov (%rbx),%r14 1f: 4d 8d 66 08 lea 0x8(%r14),%r12 23: 4d 89 e7 mov %r12,%r15 26: 49 c1 ef 03 shr $0x3,%r15 * 2a: 41 80 3c 2f 00 cmpb $0x0,(%r15,%rbp,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 4c 89 e7 mov %r12,%rdi 34: e8 9e 60 b8 fd call 0xfdb860d7 39: 49 83 3c 24 00 cmpq $0x0,(%r12) 3e: 4c rex.WR 3f: 89 .byte 0x89 *** general protection fault in fuse_kill_sb_blk tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 26260251022fbc2f248a3d747a9b2b961b18d2d8 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/41c2a7e2-d41f-466f-8380-e05ef414bf62/config syz repro: https://ci.syzbot.org/findings/842bf23d-2982-4d44-81b0-f1e6e37301b2/syz_repro erofs (device loop0): mounted with root inode @ nid 36. /dev/loop0: Can't open blockdev Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 UID: 0 PID: 5856 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:fuse_mount_destroy fs/fuse/inode.c:1989 [inline] RIP: 0010:fuse_kill_sb_blk+0x23c/0x290 fs/fuse/inode.c:2016 Code: 00 00 00 00 00 fc ff df 4c 89 f7 e8 9e e2 f2 fe 42 80 3c 2b 00 74 08 48 89 ef e8 8f 92 de fe 48 8b 5d 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 75 92 de fe 48 8b 3b e8 3d 72 ff RSP: 0018:ffffc9000234fb08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88816c3cbc00 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: ffff888174cb6678 R08: ffff888174cb6087 R09: 1ffff1102e996c10 R10: dffffc0000000000 R11: ffffed102e996c11 R12: ffff888174cb6078 R13: dffffc0000000000 R14: ffff888174cb6000 R15: 0000000000000000 FS: 00007fb71cf006c0(0000) GS:ffff8882a8d08000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001000 CR3: 00000001be98a000 CR4: 00000000000006f0 Call Trace: <TASK> deactivate_locked_super+0xbc/0x110 fs/super.c:603 get_tree_bdev_flags+0x40e/0x560 fs/super.c:1895 fuse_get_tree+0x194/0x3b0 fs/fuse/inode.c:1877 vfs_get_tree+0x92/0x2a0 fs/super.c:1958 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3772 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3848 do_mount fs/namespace.c:4181 [inline] __do_sys_mount fs/namespace.c:4397 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4374 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb71bf9e0d9 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:00007fb71cf00028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fb71c225fa0 RCX: 00007fb71bf9e0d9 RDX: 0000200000000140 RSI: 00002000000002c0 RDI: 0000200000000240 RBP: 00007fb71c035024 R08: 0000200000000400 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb71c226038 R14: 00007fb71c225fa0 R15: 00007ffe55b01cb8 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:fuse_mount_destroy fs/fuse/inode.c:1989 [inline] RIP: 0010:fuse_kill_sb_blk+0x23c/0x290 fs/fuse/inode.c:2016 Code: 00 00 00 00 00 fc ff df 4c 89 f7 e8 9e e2 f2 fe 42 80 3c 2b 00 74 08 48 89 ef e8 8f 92 de fe 48 8b 5d 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 75 92 de fe 48 8b 3b e8 3d 72 ff RSP: 0018:ffffc9000234fb08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88816c3cbc00 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: ffff888174cb6678 R08: ffff888174cb6087 R09: 1ffff1102e996c10 R10: dffffc0000000000 R11: ffffed102e996c11 R12: ffff888174cb6078 R13: dffffc0000000000 R14: ffff888174cb6000 R15: 0000000000000000 FS: 00007fb71cf006c0(0000) GS:ffff8882a8d08000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9fb604de68 CR3: 00000001be98a000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess), 7 bytes skipped: 0: df 4c 89 f7 fisttps -0x9(%rcx,%rcx,4) 4: e8 9e e2 f2 fe call 0xfef2e2a7 9: 42 80 3c 2b 00 cmpb $0x0,(%rbx,%r13,1) e: 74 08 je 0x18 10: 48 89 ef mov %rbp,%rdi 13: e8 8f 92 de fe call 0xfede92a7 18: 48 8b 5d 00 mov 0x0(%rbp),%rbx 1c: 48 89 d8 mov %rbx,%rax 1f: 48 c1 e8 03 shr $0x3,%rax * 23: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 28: 74 08 je 0x32 2a: 48 89 df mov %rbx,%rdi 2d: e8 75 92 de fe call 0xfede92a7 32: 48 8b 3b mov (%rbx),%rdi 35: e8 .byte 0xe8 36: 3d .byte 0x3d 37: 72 ff jb 0x38 *** general protection fault in xfs_kill_sb tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 26260251022fbc2f248a3d747a9b2b961b18d2d8 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/41c2a7e2-d41f-466f-8380-e05ef414bf62/config syz repro: https://ci.syzbot.org/findings/6086312c-12df-4d69-b442-5c8a99793535/syz_repro /dev/loop1: Can't open blockdev Oops: general protection fault, probably for non-canonical address 0xdffffc0000000035: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x00000000000001a8-0x00000000000001af] CPU: 0 UID: 0 PID: 5903 Comm: syz.1.24 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:xfs_kill_sb+0x4e/0x260 fs/xfs/xfs_super.c:2335 Code: 78 06 00 00 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 83 08 96 fe 4d 8b 36 4d 8d be a8 01 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ff e8 64 08 96 fe 4d 8b 27 4d 85 e4 0f 84 RSP: 0018:ffffc900027afb50 EFLAGS: 00010206 RAX: 0000000000000035 RBX: dffffc0000000000 RCX: ffff888110aa0000 RDX: 0000000000000000 RSI: ffffffff8e46456f RDI: ffff888114d4e000 RBP: ffffc900027afc00 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: ffffffff83a0ca90 R12: dffffc0000000000 R13: ffff888114d4e000 R14: 0000000000000000 R15: 00000000000001a8 FS: 00007f104ac686c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555f35035578 CR3: 00000001bf1d2000 CR4: 00000000000006f0 Call Trace: <TASK> deactivate_locked_super+0xbc/0x110 fs/super.c:603 get_tree_bdev_flags+0x40e/0x560 fs/super.c:1895 vfs_get_tree+0x92/0x2a0 fs/super.c:1958 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3772 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3848 do_mount fs/namespace.c:4181 [inline] __do_sys_mount fs/namespace.c:4397 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4374 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1049d9e0d9 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:00007f104ac68028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f104a026090 RCX: 00007f1049d9e0d9 RDX: 0000200000000000 RSI: 00002000000001c0 RDI: 0000200000000080 RBP: 00007f1049e35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000001a0c099 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f104a026128 R14: 00007f104a026090 R15: 00007ffd22a73788 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:xfs_kill_sb+0x4e/0x260 fs/xfs/xfs_super.c:2335 Code: 78 06 00 00 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 83 08 96 fe 4d 8b 36 4d 8d be a8 01 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ff e8 64 08 96 fe 4d 8b 27 4d 85 e4 0f 84 RSP: 0018:ffffc900027afb50 EFLAGS: 00010206 RAX: 0000000000000035 RBX: dffffc0000000000 RCX: ffff888110aa0000 RDX: 0000000000000000 RSI: ffffffff8e46456f RDI: ffff888114d4e000 RBP: ffffc900027afc00 R08: ffffffff90793d37 R09: 1ffffffff20f27a6 R10: dffffc0000000000 R11: ffffffff83a0ca90 R12: dffffc0000000000 R13: ffff888114d4e000 R14: 0000000000000000 R15: 00000000000001a8 FS: 00007f104ac686c0(0000) GS:ffff88818d708000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5295e4de68 CR3: 00000001bf1d2000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 78 06 js 0x8 2: 00 00 add %al,(%rax) 4: 4c 89 f0 mov %r14,%rax 7: 48 c1 e8 03 shr $0x3,%rax b: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) f: 74 08 je 0x19 11: 4c 89 f7 mov %r14,%rdi 14: e8 83 08 96 fe call 0xfe96089c 19: 4d 8b 36 mov (%r14),%r14 1c: 4d 8d be a8 01 00 00 lea 0x1a8(%r14),%r15 23: 4c 89 f8 mov %r15,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ff mov %r15,%rdi 33: e8 64 08 96 fe call 0xfe96089c 38: 4d 8b 27 mov (%r15),%r12 3b: 4d 85 e4 test %r12,%r12 3e: 0f .byte 0xf 3f: 84 .byte 0x84 *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. To test a fix for this bug, please reply with `#syz test` (on a separate line) and attach the patch to the email. Notes: - The patch will be applied on top of the tested series (as an incremental fix). - To test a new version of the whole series, please send it directly to syzbot@lists.linux.dev. - Arguments like custom git repos and branches are not supported.
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