loop4: detected capacity change from 0 to 184 loop7: detected capacity change from 0 to 64 ================================================================== BUG: KASAN: slab-use-after-free in nsproxy_free+0x572/0x5a0 Read of size 8 at addr ffff88800c260678 by task syz-executor.1/4201 CPU: 0 UID: 255 PID: 4201 Comm: syz-executor.1 Not tainted 6.18.0-rc5-next-20251114 #1 PREEMPT(voluntary) 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 nsproxy_free+0x572/0x5a0 create_new_namespaces+0x585/0x750 copy_namespaces+0x45c/0x580 copy_process+0x26e4/0x72a0 kernel_clone+0xea/0x7f0 __do_sys_clone3+0x1f5/0x280 do_syscall_64+0xbf/0x430 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f3d4b6b19 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:00007f2f3aa2c188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f2f3d5c9f60 RCX: 00007f2f3d4b6b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 00000000200001c0 RBP: 00007f2f3d510f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe73a6624f R14: 00007f2f3aa2c300 R15: 0000000000022000 FAT-fs (loop7): bogus number of FAT structure Allocated by task 114: kasan_save_stack+0x24/0x50 FAT-fs (loop7): Can't find a valid FAT filesystem kasan_save_track+0x14/0x30 __kasan_slab_alloc+0x59/0x70 kmem_cache_alloc_noprof+0x213/0x690 __alloc_object+0x2b/0x2c0 __create_object+0x1d/0x80 kmem_cache_alloc_noprof+0x42f/0x690 security_file_alloc+0x35/0x130 init_file+0x95/0x4c0 alloc_empty_file+0x76/0x1e0 path_openat+0xe0/0x2880 do_filp_open+0x1e8/0x450 do_sys_openat2+0x104/0x1b0 __x64_sys_openat+0x142/0x200 do_syscall_64+0xbf/0x430 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+0x26f/0x500 rcu_core+0x7c8/0x1800 handle_softirqs+0x1b1/0x770 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+0x70/0x960 kmem_cache_free+0x30d/0x500 security_file_free+0x65/0xa0 __fput+0x54b/0xb50 fput_close_sync+0x10f/0x230 __x64_sys_close+0x8f/0x120 do_syscall_64+0xbf/0x430 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88800c2605c8 which belongs to the cache kmemleak_object of size 232 The buggy address is located 176 bytes inside of freed 232-byte region [ffff88800c2605c8, ffff88800c2606b0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xc260 flags: 0x100000000000000(node=0|zone=1) page_type: f5(slab) raw: 0100000000000000 ffff888008c4b780 ffffea00003958c0 dead000000000002 raw: 0000000000000000 00000000000d000d 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88800c260500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88800c260580: 00 fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb >ffff88800c260600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88800c260680: fb fb fb fb fb fb fc fc fc fc fc fc fc fc 00 00 ffff88800c260700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Oops: general protection fault, probably for non-canonical address 0xdffffc000000002e: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000170-0x0000000000000177] CPU: 0 UID: 255 PID: 4201 Comm: syz-executor.1 Tainted: G B 6.18.0-rc5-next-20251114 #1 PREEMPT(voluntary) Tainted: [B]=BAD_PAGE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:nsproxy_free+0x28a/0x5a0 Code: 02 00 00 4c 8b 65 28 4d 85 e4 74 43 e8 7f 56 30 00 49 8d bc 24 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f7 02 00 00 49 8b 9c 24 78 01 00 00 bf 08 00 00 RSP: 0018:ffff888017ac79f8 EFLAGS: 00010217 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900007e5000 RDX: 000000000000002e RSI: ffffffff8144dd61 RDI: 0000000000000174 RBP: ffff88800bdbfd00 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8664ed57 R11: ffff88801f72ac50 R12: fffffffffffffffc R13: ffff88800c6e1a1c R14: ffff88800f17d040 R15: ffff88801ba9bff8 FS: 00007f2f3aa2c700(0000) GS:ffff8880e538f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055cd076e900e CR3: 000000001f66c000 CR4: 0000000000350ef0 Call Trace: create_new_namespaces+0x585/0x750 copy_namespaces+0x45c/0x580 copy_process+0x26e4/0x72a0 kernel_clone+0xea/0x7f0 __do_sys_clone3+0x1f5/0x280 do_syscall_64+0xbf/0x430 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f3d4b6b19 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:00007f2f3aa2c188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f2f3d5c9f60 RCX: 00007f2f3d4b6b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 00000000200001c0 RBP: 00007f2f3d510f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe73a6624f R14: 00007f2f3aa2c300 R15: 0000000000022000 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:nsproxy_free+0x28a/0x5a0 Code: 02 00 00 4c 8b 65 28 4d 85 e4 74 43 e8 7f 56 30 00 49 8d bc 24 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f7 02 00 00 49 8b 9c 24 78 01 00 00 bf 08 00 00 RSP: 0018:ffff888017ac79f8 EFLAGS: 00010217 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900007e5000 RDX: 000000000000002e RSI: ffffffff8144dd61 RDI: 0000000000000174 RBP: ffff88800bdbfd00 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8664ed57 R11: ffff88801f72ac50 R12: fffffffffffffffc R13: ffff88800c6e1a1c R14: ffff88800f17d040 R15: ffff88801ba9bff8 FS: 00007f2f3aa2c700(0000) GS:ffff8880e538f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055cd076e900e CR3: 000000001f66c000 CR4: 0000000000350ef0 loop4: detected capacity change from 0 to 184 loop1: detected capacity change from 0 to 264192 vfat: Bad value for 'nfs' vfat: Unknown parameter '“Ü ¿ÚôµÌª®rù Yï{SIÌ' loop7: detected capacity change from 0 to 2048 loop4: detected capacity change from 0 to 184 loop7: detected capacity change from 0 to 2048 sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s sr 1:0:0:0: [sr0] tag#0 Sense Key : Not Ready [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Medium not present sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 02 00 00 06 00 I/O error, dev sr0, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 2 sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 8 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 8, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 9 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 9, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 10 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 10, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 11 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 11, async page read Bluetooth: hci0: Opcode 0x0c1a failed: -4 Bluetooth: hci0: Opcode 0x0406 failed: -4 sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 12 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 12, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 13 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 13, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 14 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 14, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 15 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 15, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer I/O error, dev sr0, sector 8 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev sr0, logical block 8, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer Buffer I/O error on dev sr0, logical block 9, async page read sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer Bluetooth: hci0: Opcode 0x0406 failed: -4 sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer sr 1:0:0:0: [sr0] tag#0 unaligned transfer Bluetooth: hci1: Opcode 0x0c1a failed: -4 Bluetooth: hci1: Opcode 0x0406 failed: -4 Bluetooth: hci1: Opcode 0x0406 failed: -4 Bluetooth: hci2: Opcode 0x0c1a failed: -4 Bluetooth: hci2: Opcode 0x0406 failed: -4 Bluetooth: hci2: Opcode 0x0406 failed: -4 sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s sr 1:0:0:0: [sr0] tag#0 Sense Key : Not Ready [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Medium not present sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 02 00 00 02 00 Bluetooth: hci4: Opcode 0x0c1a failed: -4 Bluetooth: hci4: Opcode 0x0406 failed: -4 Bluetooth: hci4: Opcode 0x0406 failed: -4 Bluetooth: hci3: Opcode 0x0c1a failed: -4 Bluetooth: hci3: Opcode 0x0406 failed: -4 Bluetooth: hci3: Opcode 0x0406 failed: -4 Bluetooth: hci5: Opcode 0x0c1a failed: -4 Bluetooth: hci5: Opcode 0x0406 failed: -4 Bluetooth: hci5: Opcode 0x0406 failed: -4 Bluetooth: hci6: Opcode 0x0c1a failed: -4 Bluetooth: hci6: Opcode 0x0406 failed: -4 Bluetooth: hci6: Opcode 0x0406 failed: -4 Bluetooth: hci7: Opcode 0x0c1a failed: -4 Bluetooth: hci7: Opcode 0x0406 failed: -4 Bluetooth: hci7: Opcode 0x0406 failed: -4 Bluetooth: hci0: command 0x0c1a tx timeout Bluetooth: hci2: command 0x0c1a tx timeout Bluetooth: hci1: command 0x0c1a tx timeout Bluetooth: hci7: command 0x0c1a tx timeout Bluetooth: hci6: command 0x0c1a tx timeout Bluetooth: hci5: command 0x0c1a tx timeout Bluetooth: hci3: command 0x0c1a tx timeout Bluetooth: hci4: command 0x0c1a tx timeout ---------------- Code disassembly (best guess): 0: 02 00 add (%rax),%al 2: 00 4c 8b 65 add %cl,0x65(%rbx,%rcx,4) 6: 28 4d 85 sub %cl,-0x7b(%rbp) 9: e4 74 in $0x74,%al b: 43 e8 7f 56 30 00 rex.XB callq 0x305690 11: 49 8d bc 24 78 01 00 lea 0x178(%r12),%rdi 18: 00 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 20: fc ff df 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 f7 02 00 00 jne 0x32b 34: 49 8b 9c 24 78 01 00 mov 0x178(%r12),%rbx 3b: 00 3c: bf .byte 0xbf 3d: 08 00 or %al,(%rax)