Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 5381 Comm: syz-executor.1 Not tainted 6.18.0-rc7-next-20251128 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:__fput+0x1cc/0xb50
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f6 08 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 7e 68 49 8d 7f 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c9 08 00 00 48 ba 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff88801be07e08 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: ffff88805014ca80 RCX: ffffc90000e08000
RDX: 0000000000000005 RSI: ffffffff81b955f2 RDI: 0000000000000028
RBP: ffff88802070fdc0 R08: 0000000000000000 R09: ffffed10037c0fd4
R10: 0000000004000000 R11: 0000000000000001 R12: ffff88802070fe00
R13: 0000000000000010 R14: ffff8880192c7780 R15: 0000000000000000
FS: 00007ff579671700(0000) GS:ffff8880e5368000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8e7e321000 CR3: 000000005026c000 CR4: 0000000000350ef0
Call Trace:
fput_close_sync+0x10f/0x230
__x64_sys_close+0x8f/0x120
do_syscall_64+0xbf/0x420
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff57c0fbb19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff579671188 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007ff57c20ef60 RCX: 00007ff57c0fbb19
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007ff57c155f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc67b3144f R14: 00007ff579671300 R15: 0000000000022000
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__fput+0x1cc/0xb50
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f6 08 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 7e 68 49 8d 7f 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c9 08 00 00 48 ba 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff88801be07e08 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: ffff88805014ca80 RCX: ffffc90000e08000
RDX: 0000000000000005 RSI: ffffffff81b955f2 RDI: 0000000000000028
RBP: ffff88802070fdc0 R08: 0000000000000000 R09: ffffed10037c0fd4
R10: 0000000004000000 R11: 0000000000000001 R12: ffff88802070fe00
R13: 0000000000000010 R14: ffff8880192c7780 R15: 0000000000000000
FS: 00007ff579671700(0000) GS:ffff8880e5368000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8e7e321000 CR3: 000000005026c000 CR4: 0000000000350ef0
loop7: detected capacity change from 0 to 4132
EXT4-fs (loop7): couldn't mount as ext2 due to feature incompatibilities
loop7: detected capacity change from 0 to 4132
EXT4-fs (loop7): couldn't mount as ext2 due to feature incompatibilities
loop7: detected capacity change from 0 to 4132
EXT4-fs (loop7): couldn't mount as ext2 due to feature incompatibilities
==================================================================
BUG: KASAN: slab-use-after-free in rwsem_down_write_slowpath+0x1522/0x1670
Read of size 4 at addr ffff888015d35374 by task syz-executor.3/5421
CPU: 0 UID: 0 PID: 5421 Comm: syz-executor.3 Tainted: G D 6.18.0-rc7-next-20251128 #1 PREEMPT(voluntary)
Tainted: [D]=DIE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack_lvl+0xca/0x120
print_report+0xcb/0x610
kasan_report+0xca/0x100
rwsem_down_write_slowpath+0x1522/0x1670
down_write_nested+0x1c6/0x1f0
start_creating_noperm+0x84/0xd0
do_mq_open+0x25f/0x980
__x64_sys_mq_open+0x14f/0x1e0
do_syscall_64+0xbf/0x420
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf188f0b19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faf15e66188 EFLAGS: 00000246 ORIG_RAX: 00000000000000f0
RAX: ffffffffffffffda RBX: 00007faf18a03f60 RCX: 00007faf188f0b19
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 00007faf1894af6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc77d1980f R14: 00007faf15e66300 R15: 0000000000022000
Allocated by task 5412:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x59/0x70
kmem_cache_alloc_node_noprof+0x228/0x730
copy_process+0x460/0x7230
kernel_clone+0xea/0x7c0
__do_sys_clone+0xce/0x120
do_syscall_64+0xbf/0x420
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 14:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x43/0x70
kmem_cache_free+0x2cd/0x660
rcu_core+0x73c/0x1ed0
handle_softirqs+0x1b1/0x740
run_ksoftirqd+0x2e/0x60
smpboot_thread_fn+0x41d/0x9d0
kthread+0x3c8/0x740
ret_from_fork+0x67a/0x7a0
ret_from_fork_asm+0x1a/0x30
Last potentially related work creation:
kasan_save_stack+0x24/0x50
kasan_record_aux_stack+0x89/0xa0
__call_rcu_common.constprop.0+0x70/0xad0
delayed_put_task_struct+0xde/0x230
rcu_core+0x73c/0x1ed0
handle_softirqs+0x1b1/0x740
run_ksoftirqd+0x2e/0x60
smpboot_thread_fn+0x41d/0x9d0
kthread+0x3c8/0x740
ret_from_fork+0x67a/0x7a0
ret_from_fork_asm+0x1a/0x30
Second to last potentially related work creation:
kasan_save_stack+0x24/0x50
kasan_record_aux_stack+0x89/0xa0
__call_rcu_common.constprop.0+0x70/0xad0
put_task_struct_rcu_user+0x75/0xc0
__schedule+0x1003/0x46a0
schedule+0xdb/0x390
exit_to_user_mode_loop+0x73/0x4d0
do_syscall_64+0x3c3/0x420
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888015d35340
which belongs to the cache task_struct of size 6848
The buggy address is located 52 bytes inside of
freed 6848-byte region [ffff888015d35340, ffff888015d36e00)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15d30
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88800eabd201
flags: 0x100000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0100000000000040 ffff88800944c640 ffffea00003d7000 0000000000000002
raw: 0000000000000000 0000000000040004 00000000f5000000 ffff88800eabd201
head: 0100000000000040 ffff88800944c640 ffffea00003d7000 0000000000000002
head: 0000000000000000 0000000000040004 00000000f5000000 ffff88800eabd201
head: 0100000000000003 ffffea0000574c01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888015d35200: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
ffff888015d35280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888015d35300: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
^
ffff888015d35380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888015d35400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
loop7: detected capacity change from 0 to 4132
EXT4-fs (loop7): couldn't mount as ext2 due to feature incompatibilities
tmpfs: Unknown parameter 'huge}alw„ys'
tmpfs: Unknown parameter 'huge}alw„ys'
----------------
Code disassembly (best guess):
0: 48 89 fa mov %rdi,%rdx
3: 48 c1 ea 03 shr $0x3,%rdx
7: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
b: 0f 85 f6 08 00 00 jne 0x907
11: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
18: fc ff df
1b: 4d 8b 7e 68 mov 0x68(%r14),%r15
1f: 49 8d 7f 28 lea 0x28(%r15),%rdi
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 c9 08 00 00 jne 0x8fd
34: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
3b: fc ff df
3e: 49 rex.WB
3f: 8b .byte 0x8b