syzbot

9pnet: Found fid 4 not clunked
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BUG: KASAN: slab-use-after-free in p9_fid_destroy+0xb5/0xd0 net/9p/client.c:884
Read of size 8 at addr ffff888045b3a300 by task syz-executor.0/14260

CPU: 2 PID: 14260 Comm: syz-executor.0 Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 p9_fid_destroy+0xb5/0xd0 net/9p/client.c:884
 p9_client_destroy+0x14c/0x480 net/9p/client.c:1070
 v9fs_session_close+0x49/0x2d0 fs/9p/v9fs.c:506
 v9fs_kill_super+0x4d/0xa0 fs/9p/vfs_super.c:196
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472
 deactivate_super+0xde/0x100 fs/super.c:505
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa29d87efd7
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe67ee7868 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa29d87efd7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe67ee7920
RBP: 00007ffe67ee7920 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe67ee89e0
R13: 00007fa29d8c83b9 R14: 0000000000059723 R15: 000000000000001e
 </TASK>

Allocated by task 18144:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kmalloc include/linux/slab.h:628 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 p9_fid_create+0x45/0x470 net/9p/client.c:853
 p9_client_walk+0xc6/0x550 net/9p/client.c:1154
 clone_fid fs/9p/fid.h:23 [inline]
 v9fs_fid_clone fs/9p/fid.h:33 [inline]
 v9fs_file_open+0x5b5/0xae0 fs/9p/vfs_file.c:56
 do_dentry_open+0x8da/0x18c0 fs/open.c:955
 do_open fs/namei.c:3642 [inline]
 path_openat+0x1dfb/0x2990 fs/namei.c:3799
 do_filp_open+0x1dc/0x430 fs/namei.c:3826
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_open fs/open.c:1429 [inline]
 __se_sys_open fs/open.c:1425 [inline]
 __x64_sys_open+0x154/0x1e0 fs/open.c:1425
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 1185:
 kasan_save_stack+0x33/0x60 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:579
 poison_slab_object mm/kasan/common.c:240 [inline]
 __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2106 [inline]
 slab_free mm/slub.c:4280 [inline]
 kfree+0x129/0x390 mm/slub.c:4390
 p9_client_clunk+0x12a/0x170 net/9p/client.c:1456
 p9_fid_put include/net/9p/client.h:278 [inline]
 v9fs_free_request+0xdc/0x110 fs/9p/vfs_addr.c:128
 netfs_free_request+0x22f/0x6b0 fs/netfs/objects.c:97
 netfs_put_request+0x19b/0x1f0 fs/netfs/objects.c:130
 netfs_free_subrequest fs/netfs/objects.c:178 [inline]
 netfs_put_subrequest+0x408/0x6c0 fs/netfs/objects.c:192
 v9fs_upload_to_server fs/9p/vfs_addr.c:36 [inline]
 v9fs_upload_to_server_worker+0x18c/0x3b0 fs/9p/vfs_addr.c:44
 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3267
 process_scheduled_works kernel/workqueue.c:3348 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3429
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff888045b3a300
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 freed 96-byte region [ffff888045b3a300, ffff888045b3a360)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x45b3a
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888015042780 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 72, tgid 598568644 (kworker/u32:4), ts 72, free_ts 56430540636
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2391
 ___slab_alloc+0x66d/0x1790 mm/slub.c:3525
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmalloc_trace+0x2fb/0x330 mm/slub.c:3992
 kmalloc include/linux/slab.h:628 [inline]
 dst_cow_metrics_generic+0x4c/0x1f0 net/core/dst.c:178
 dst_metrics_write_ptr include/net/dst.h:133 [inline]
 dst_metric_set include/net/dst.h:194 [inline]
 icmp6_dst_alloc+0x370/0x4a0 net/ipv6/route.c:3286
 ndisc_send_skb+0x1279/0x1c30 net/ipv6/ndisc.c:489
 ndisc_send_rs+0x12b/0x690 net/ipv6/ndisc.c:719
 addrconf_dad_completed+0x4a1/0x1060 net/ipv6/addrconf.c:4358
 addrconf_dad_work+0x807/0x1500 net/ipv6/addrconf.c:4266
 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3267
 process_scheduled_works kernel/workqueue.c:3348 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3429
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
page last free pid 5269 tgid 5269 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347
 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:468
 exit_mmap+0x3da/0xb90 mm/mmap.c:3280
 __mmput+0x12a/0x4d0 kernel/fork.c:1346
 mmput+0x62/0x70 kernel/fork.c:1368
 exit_mm kernel/exit.c:569 [inline]
 do_exit+0x999/0x2c10 kernel/exit.c:865
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888045b3a200: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888045b3a280: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888045b3a300: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff888045b3a380: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888045b3a400: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
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