Hello maintainers,
I would like to report a kernel panic found using syzkaller on a 6.16.0-rc6.
The kernel log shows two distinct but closely timed crash reports,
which I guess are related.
1. An XFS assertion failure: Assertion failed: flags &
IOMAP_DIO_OVERWRITE_ONLY, file: fs/xfs/xfs_file.c, line: 876 triggered
by a write() system call in xfs_file_dio_write_unaligned.
2. A KASAN use-after-free report on a task_struct object, triggered
during an ioctl() call (likely FICLONE or FIDEDUPERANGE). The crash
occurs in rwsem_down_write_slowpath when trying to lock an inode via
xfs_reflink_remap_prep.
Unfortunately, I have not been able to create a standalone C
reproducer, and attempts to use syzkaller's repro tool on the syz-prog
have not reliably triggered the bug again.
Below are the full kernel oops messages:
=======================================================
XFS: Assertion failed: flags & IOMAP_DIO_OVERWRITE_ONLY, file:
fs/xfs/xfs_file.c, line: 876
------------[ cut here ]------------
kernel BUG at fs/xfs/xfs_message.c:102!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 467280 Comm: syz-executor.0 Not tainted
6.16.0-rc6-00002-g155a3c003e55-dirty #14 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:assfail+0x9d/0xa0 fs/xfs/xfs_message.c:102
Code: 75 22 e8 b6 88 3a ff 90 0f 0b 90 5b 5d 41 5c 41 5d e9 c7 2d 78
02 48 c7 c7 78 af 63 a1 e8 2b 5a 6f ff eb ca e8 94 88 3a ff 90 <0f> 0b
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f
RSP: 0018:ffff888113327c18 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9db22a2c
RDX: ffff88816e9c2dc0 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1022664f18
R10: 0000000000000001 R11: 737341203a534658 R12: ffffffffa05c63a0
R13: 000000000000036c R14: ffff888113327c70 R15: 0000000000000000
FS: 00007f1f761ae640(0000) GS:ffff88840c16a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1f761adff0 CR3: 00000001e3458000 CR4: 00000000000006f0
Call Trace:
<TASK>
xfs_file_dio_write_unaligned+0x5a9/0x620 fs/xfs/xfs_file.c:876
xfs_file_dio_write fs/xfs/xfs_file.c:909 [inline]
xfs_file_write_iter+0x919/0xb50 fs/xfs/xfs_file.c:1124
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0xa78/0xd70 fs/read_write.c:686
ksys_write+0x124/0x240 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa8/0x270 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f76e6002d
Code: c3 e8 97 2b 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1f761ae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1f76f9c050 RCX: 00007f1f76e6002d
RDX: 0000000018000000 RSI: 0000000020000400 RDI: 0000000000000003
RBP: 00007f1f76ec14a6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1f76f9c050 R15: 00007f1f7618e000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:assfail+0x9d/0xa0 fs/xfs/xfs_message.c:102
Code: 75 22 e8 b6 88 3a ff 90 0f 0b 90 5b 5d 41 5c 41 5d e9 c7 2d 78
02 48 c7 c7 78 af 63 a1 e8 2b 5a 6f ff eb ca e8 94 88 3a ff 90 <0f> 0b
90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f
RSP: 0018:ffff888113327c18 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9db22a2c
RDX: ffff88816e9c2dc0 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1022664f18
R10: 0000000000000001 R11: 737341203a534658 R12: ffffffffa05c63a0
R13: 000000000000036c R14: ffff888113327c70 R15: 0000000000000000
FS: 00007f1f761ae640(0000) GS:ffff88840c16a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1f761adff0 CR3: 00000001e3458000 CR4: 00000000000006f0
==================================================================
BUG: KASAN: slab-use-after-free in owner_on_cpu
include/linux/sched.h:2236 [inline]
BUG: KASAN: slab-use-after-free in rwsem_can_spin_on_owner
kernel/locking/rwsem.c:723 [inline]
BUG: KASAN: slab-use-after-free in
rwsem_down_write_slowpath+0x109e/0x1100 kernel/locking/rwsem.c:1111
Read of size 4 at addr ffff88816e9c2df4 by task syz-executor.0/467290
CPU: 5 UID: 0 PID: 467290 Comm: syz-executor.0 Tainted: G D
6.16.0-rc6-00002-g155a3c003e55-dirty #14 PREEMPT(voluntary)
Tainted: [D]=DIE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcb/0x5f0 mm/kasan/report.c:480
kasan_report+0xb8/0xf0 mm/kasan/report.c:593
owner_on_cpu include/linux/sched.h:2236 [inline]
rwsem_can_spin_on_owner kernel/locking/rwsem.c:723 [inline]
rwsem_down_write_slowpath+0x109e/0x1100 kernel/locking/rwsem.c:1111
__down_write_common kernel/locking/rwsem.c:1304 [inline]
__down_write kernel/locking/rwsem.c:1313 [inline]
down_write+0x114/0x130 kernel/locking/rwsem.c:1578
inode_lock include/linux/fs.h:869 [inline]
xfs_iolock_two_inodes_and_break_layout fs/xfs/xfs_inode.c:2705 [inline]
xfs_ilock2_io_mmap+0x18e/0x4f0 fs/xfs/xfs_inode.c:2781
xfs_reflink_remap_prep+0x98/0x940 fs/xfs/xfs_reflink.c:1667
xfs_file_remap_range+0x202/0xc10 fs/xfs/xfs_file.c:1507
vfs_dedupe_file_range_one+0x5a3/0x6d0 fs/remap_range.c:483
vfs_dedupe_file_range+0x4f5/0x7f0 fs/remap_range.c:551
ioctl_file_dedupe_range fs/ioctl.c:443 [inline]
do_vfs_ioctl+0x103b/0x17d0 fs/ioctl.c:857
__do_sys_ioctl fs/ioctl.c:905 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x116/0x210 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa8/0x270 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f76e6002d
Code: c3 e8 97 2b 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1f761cf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1f76f9bf80 RCX: 00007f1f76e6002d
RDX: 0000000020000140 RSI: 00000000c0189436 RDI: 0000000000000003
RBP: 00007f1f76ec14a6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1f76f9bf80 R15: 00007f1f761af000
</TASK>
Allocated by task 467239:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x59/0x70 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4148 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
kmem_cache_alloc_node_noprof+0xf7/0x340 mm/slub.c:4249
alloc_task_struct_node kernel/fork.c:183 [inline]
dup_task_struct kernel/fork.c:869 [inline]
copy_process+0x491/0x6a80 kernel/fork.c:1999
kernel_clone+0xe3/0x8e0 kernel/fork.c:2599
__do_sys_clone3+0x1f6/0x280 kernel/fork.c:2903
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa8/0x270 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 164:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x38/0x50 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2381 [inline]
slab_free mm/slub.c:4643 [inline]
kmem_cache_free+0x130/0x380 mm/slub.c:4745
put_task_struct include/linux/sched/task.h:145 [inline]
delayed_put_task_struct+0x171/0x1c0 kernel/exit.c:230
rcu_do_batch kernel/rcu/tree.c:2576 [inline]
rcu_core+0x5f6/0x1a20 kernel/rcu/tree.c:2832
handle_softirqs+0x176/0x530 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu kernel/softirq.c:680 [inline]
irq_exit_rcu+0xaf/0xe0 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0x70/0x80 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
Last potentially related work creation:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:47
kasan_record_aux_stack+0x8c/0xa0 mm/kasan/generic.c:548
__call_rcu_common.constprop.0+0x70/0x930 kernel/rcu/tree.c:3094
put_task_struct_rcu_user+0x75/0xc0 kernel/exit.c:236
context_switch kernel/sched/core.c:5400 [inline]
__schedule+0xeba/0x2960 kernel/sched/core.c:6786
schedule_idle+0x5c/0x90 kernel/sched/core.c:6905
do_idle+0x266/0x480 kernel/sched/idle.c:353
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
start_secondary+0x1b8/0x210 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x148
The buggy address belongs to the object at ffff88816e9c2dc0
which belongs to the cache task_struct of size 3776
The buggy address is located 52 bytes inside of
freed 3776-byte region [ffff88816e9c2dc0, ffff88816e9c3c80)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16e9c0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x200000000000040(head|node=0|zone=2)
page_type: f5(slab)
raw: 0200000000000040 ffff8881001cadc0 ffffea0004023600 dead000000000006
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 0200000000000040 ffff8881001cadc0 ffffea0004023600 dead000000000006
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 0200000000000003 ffffea0005ba7001 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88816e9c2c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88816e9c2d00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88816e9c2d80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
^
ffff88816e9c2e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88816e9c2e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
