==================================================================
BUG: KASAN: use-after-free in smc_fback_error_report+0x96/0xa0 net/smc/af_smc.c:670
Read of size 8 at addr ffff8880795af0e8 by task kworker/u4:8/4035

CPU: 0 PID: 4035 Comm: kworker/u4:8 Not tainted 5.17.0-rc6-syzkaller-00228-gac84e82f78cb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 smc_fback_error_report+0x96/0xa0 net/smc/af_smc.c:670
 sk_error_report+0x35/0x310 net/core/sock.c:340
 tcp_write_err net/ipv4/tcp_timer.c:71 [inline]
 tcp_probe_timer net/ipv4/tcp_timer.c:395 [inline]
 tcp_write_timer_handler+0x437/0xbc0 net/ipv4/tcp_timer.c:626
 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:642
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734
 __run_timers kernel/time/timer.c:1715 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:check_region_inline mm/kasan/generic.c:175 [inline]
RIP: 0010:kasan_check_range+0x27/0x180 mm/kasan/generic.c:189
Code: 00 00 90 48 85 f6 0f 84 3c 01 00 00 49 89 f9 41 54 44 0f b6 c2 49 01 f1 55 53 0f 82 18 01 00 00 48 b8 ff ff ff ff ff 7f ff ff <48> 39 c7 0f 86 05 01 00 00 49 83 e9 01 48 89 fd 48 b8 00 00 00 00
RSP: 0018:ffffc90006247bb0 EFLAGS: 00000282
RAX: ffff7fffffffffff RBX: 0000000000000000 RCX: ffffffff815ca931
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d93e890
RBP: 1ffff92000c48f7c R08: 0000000000000000 R09: ffffffff8d93e898
R10: ffffffff88e74851 R11: 0000000000000000 R12: ffffffff8bb81ae0
R13: 0000000000000000 R14: dffffc0000000000 R15: 000000000000030a
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 cpumask_test_cpu include/linux/cpumask.h:379 [inline]
 cpu_online include/linux/cpumask.h:921 [inline]
 trace_lock_release include/trace/events/lock.h:58 [inline]
 lock_release+0xa1/0x720 kernel/locking/lockdep.c:5650
 rcu_lock_release include/linux/rcupdate.h:273 [inline]
 rcu_read_unlock include/linux/rcupdate.h:727 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0x86b/0xfa0 net/batman-adv/network-coding.c:719
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

The buggy address belongs to the page:
page:ffffea0001e56bc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x795af
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 ffffffff00000101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x3c2220(__GFP_HIGH|__GFP_ATOMIC|__GFP_NOWARN|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE), pid 3745, ts 412631937141, free_ts 413432286103
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
 __alloc_pages_node include/linux/gfp.h:572 [inline]
 kmem_getpages mm/slab.c:1378 [inline]
 cache_grow_begin+0x75/0x390 mm/slab.c:2584
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2957
 ____cache_alloc mm/slab.c:3040 [inline]
 ____cache_alloc mm/slab.c:3023 [inline]
 slab_alloc_node mm/slab.c:3241 [inline]
 kmem_cache_alloc_node_trace+0x49c/0x5b0 mm/slab.c:3609
 __do_kmalloc_node mm/slab.c:3631 [inline]
 __kmalloc_node_track_caller+0x38/0x60 mm/slab.c:3646
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0xde/0x340 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1158 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:745 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:802 [inline]
 nsim_dev_trap_report_work+0x29a/0xbc0 drivers/net/netdevsim/dev.c:843
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3404
 slab_destroy mm/slab.c:1630 [inline]
 slabs_destroy+0x89/0xc0 mm/slab.c:1650
 cache_flusharray mm/slab.c:3410 [inline]
 ___cache_free+0x303/0x600 mm/slab.c:3472
 qlink_free mm/kasan/quarantine.c:157 [inline]
 qlist_free_all+0x50/0x1a0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:446
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:732 [inline]
 slab_alloc mm/slab.c:3315 [inline]
 kmem_cache_alloc+0x265/0x560 mm/slab.c:3499
 p9_tag_alloc net/9p/client.c:266 [inline]
 p9_client_prepare_req.part.0+0x3a/0xc20 net/9p/client.c:697
 p9_client_prepare_req net/9p/client.c:802 [inline]
 p9_client_rpc+0x21c/0x1260 net/9p/client.c:734
 p9_client_read_once+0x23b/0x600 net/9p/client.c:1602
 p9_client_read+0x13b/0x1a0 net/9p/client.c:1561
 v9fs_dir_readdir+0x4ac/0x6d0 fs/9p/vfs_dir.c:113
 iterate_dir+0x576/0x700 fs/readdir.c:65
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64 fs/readdir.c:354 [inline]
 __x64_sys_getdents64+0x13a/0x2c0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

Memory state around the buggy address:
 ffff8880795aef80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880795af000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880795af080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                          ^
 ffff8880795af100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880795af180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	90                   	nop
   3:	48 85 f6             	test   %rsi,%rsi
   6:	0f 84 3c 01 00 00    	je     0x148
   c:	49 89 f9             	mov    %rdi,%r9
   f:	41 54                	push   %r12
  11:	44 0f b6 c2          	movzbl %dl,%r8d
  15:	49 01 f1             	add    %rsi,%r9
  18:	55                   	push   %rbp
  19:	53                   	push   %rbx
  1a:	0f 82 18 01 00 00    	jb     0x138
  20:	48 b8 ff ff ff ff ff 	movabs $0xffff7fffffffffff,%rax
  27:	7f ff ff
* 2a:	48 39 c7             	cmp    %rax,%rdi <-- trapping instruction
  2d:	0f 86 05 01 00 00    	jbe    0x138
  33:	49 83 e9 01          	sub    $0x1,%r9
  37:	48 89 fd             	mov    %rdi,%rbp
  3a:	48                   	rex.W
  3b:	b8 00 00 00 00       	mov    $0x0,%eax