syzbot

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BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:264 [inline]
BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:307 [inline]
BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:325 [inline]
BUG: KASAN: slab-use-after-free in p9_fid_put include/net/9p/client.h:275 [inline]
BUG: KASAN: slab-use-after-free in v9fs_free_request+0x5f/0xe0 fs/9p/vfs_addr.c:128
Write of size 4 at addr ffff88801e6bfb8c by task kworker/u8:5/964

CPU: 0 PID: 964 Comm: kworker/u8:5 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events_unbound v9fs_upload_to_server_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
 __refcount_sub_and_test include/linux/refcount.h:264 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 p9_fid_put include/net/9p/client.h:275 [inline]
 v9fs_free_request+0x5f/0xe0 fs/9p/vfs_addr.c:128
 netfs_free_request+0x244/0x600 fs/netfs/objects.c:97
 v9fs_upload_to_server fs/9p/vfs_addr.c:36 [inline]
 v9fs_upload_to_server_worker+0x200/0x3e0 fs/9p/vfs_addr.c:44
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 8618:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace+0x1db/0x360 mm/slub.c:3997
 kmalloc include/linux/slab.h:628 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 p9_fid_create+0x4f/0x230 net/9p/client.c:853
 p9_client_walk+0x103/0x690 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+0x285/0xa60 fs/9p/vfs_file.c:56
 do_dentry_open+0x907/0x15a0 fs/open.c:955
 do_open fs/namei.c:3642 [inline]
 path_openat+0x2860/0x3240 fs/namei.c:3799
 do_filp_open+0x235/0x490 fs/namei.c:3826
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_creat fs/open.c:1497 [inline]
 __se_sys_creat fs/open.c:1491 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1491
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5081:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 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+0x153/0x3a0 mm/slub.c:4390
 p9_fid_destroy net/9p/client.c:889 [inline]
 p9_client_destroy+0x1fb/0x660 net/9p/client.c:1070
 v9fs_session_close+0x51/0x210 fs/9p/v9fs.c:506
 v9fs_kill_super+0x5c/0x90 fs/9p/vfs_super.c:196
 deactivate_locked_super+0xc4/0x130 fs/super.c:472
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
 task_work_run+0x24f/0x310 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+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88801e6bfb80
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 12 bytes inside of
 freed 96-byte region [ffff88801e6bfb80, ffff88801e6bfbe0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1e6bf
flags: 0xfff80000000800(slab|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000800 ffff888015041780 ffffea0000980940 dead000000000002
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 0x12820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 10, tgid -1120101551 (kworker/u8:0), ts 10, free_ts 76187340243
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 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+0x5f/0x160 mm/slub.c:2175
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2391
 ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmalloc_trace+0x269/0x360 mm/slub.c:3992
 kmalloc include/linux/slab.h:628 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:990 [inline]
 nsim_fib_event_nb+0x17c/0x10b0 drivers/net/netdevsim/fib.c:1043
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 atomic_notifier_call_chain+0xdb/0x180 kernel/notifier.c:231
 call_fib_notifiers+0x31/0x60 net/core/fib_notifier.c:35
 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:404 [inline]
 fib6_add_rt2node net/ipv6/ip6_fib.c:1233 [inline]
 fib6_add+0x1bd5/0x4430 net/ipv6/ip6_fib.c:1490
 __ip6_ins_rt net/ipv6/route.c:1313 [inline]
 ip6_ins_rt+0x106/0x170 net/ipv6/route.c:1323
 __ipv6_ifa_notify+0x5ca/0x11f0 net/ipv6/addrconf.c:6266
 ipv6_ifa_notify net/ipv6/addrconf.c:6305 [inline]
 addrconf_dad_completed+0x181/0xcd0 net/ipv6/addrconf.c:4318
 addrconf_dad_work+0xdc2/0x16f0
page last free pid 5083 tgid 5083 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+0x97b/0xaa0 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 __slab_free+0x31b/0x3d0 mm/slub.c:4192
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_node+0x194/0x380 mm/slub.c:3888
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:658
 netlink_sendmsg+0x637/0xcb0 net/netlink/af_netlink.c:1880
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2199
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88801e6bfa80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff88801e6bfb00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff88801e6bfb80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                      ^
 ffff88801e6bfc00: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff88801e6bfc80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
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