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BUG: KASAN: slab-out-of-bounds in fuse_retrieve fs/fuse/dev.c:1911 [inline]
BUG: KASAN: slab-out-of-bounds in fuse_notify_retrieve fs/fuse/dev.c:1959 [inline]
BUG: KASAN: slab-out-of-bounds in fuse_notify fs/fuse/dev.c:2067 [inline]
BUG: KASAN: slab-out-of-bounds in fuse_dev_do_write+0x308b/0x3420 fs/fuse/dev.c:2158
Write of size 4 at addr ffff88803b07fcdc by task syz.0.17/6132

CPU: 3 UID: 0 PID: 6132 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 fuse_retrieve fs/fuse/dev.c:1911 [inline]
 fuse_notify_retrieve fs/fuse/dev.c:1959 [inline]
 fuse_notify fs/fuse/dev.c:2067 [inline]
 fuse_dev_do_write+0x308b/0x3420 fs/fuse/dev.c:2158
 fuse_dev_write+0x155/0x1e0 fs/fuse/dev.c:2242
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff87658ebe9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff8773f4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff8767b5fa0 RCX: 00007ff87658ebe9
RDX: 0000000000000030 RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007ff876611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff8767b6038 R14: 00007ff8767b5fa0 R15: 00007ffee247e838
 </TASK>

Allocated by task 6132:
 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:388 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4365 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4377
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 fuse_retrieve fs/fuse/dev.c:1879 [inline]
 fuse_notify_retrieve fs/fuse/dev.c:1959 [inline]
 fuse_notify fs/fuse/dev.c:2067 [inline]
 fuse_dev_do_write+0x1c50/0x3420 fs/fuse/dev.c:2158
 fuse_dev_write+0x155/0x1e0 fs/fuse/dev.c:2242
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803b07fc00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 4 bytes to the right of
 allocated 216-byte region [ffff88803b07fc00, ffff88803b07fcd8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3b07e
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b842b40 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b842b40 dead000000000122 0000000000000000
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000ec1f81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 841, tgid 841 (kworker/3:2), ts 75782189854, free_ts 69282332674
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2487 [inline]
 allocate_slab mm/slub.c:2655 [inline]
 new_slab+0x247/0x330 mm/slub.c:2709
 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981
 __slab_alloc_node mm/slub.c:4056 [inline]
 slab_alloc_node mm/slub.c:4217 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 batadv_bla_get_backbone_gw+0xbe/0xc40 net/batman-adv/bridge_loop_avoidance.c:508
 batadv_bla_update_own_backbone_gw.isra.0+0x4e/0x170 net/batman-adv/bridge_loop_avoidance.c:571
 batadv_bla_tx+0x144/0x21b0 net/batman-adv/bridge_loop_avoidance.c:2105
 batadv_interface_tx+0x5e7/0x1b80 net/batman-adv/mesh-interface.c:227
 __netdev_start_xmit include/linux/netdevice.h:5222 [inline]
 netdev_start_xmit include/linux/netdevice.h:5231 [inline]
 xmit_one net/core/dev.c:3839 [inline]
 dev_hard_start_xmit+0x94/0x740 net/core/dev.c:3855
 __dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4725
 dev_queue_xmit include/linux/netdevice.h:3361 [inline]
 neigh_hh_output include/net/neighbour.h:531 [inline]
 neigh_output include/net/neighbour.h:545 [inline]
 ip6_finish_output2+0xe98/0x2020 net/ipv6/ip6_output.c:141
 __ip6_finish_output+0x3cd/0x1010 net/ipv6/ip6_output.c:215
page last free pid 5992 tgid 5992 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4281
 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:659
 alloc_skb include/linux/skbuff.h:1336 [inline]
 netlink_alloc_large_skb+0x69/0x130 net/netlink/af_netlink.c:1186
 netlink_sendmsg+0x6a1/0xdd0 net/netlink/af_netlink.c:1871
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 ____sys_sendmsg+0xa95/0xc70 net/socket.c:2614
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668
 __sys_sendmsg+0x16d/0x220 net/socket.c:2700
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803b07fb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803b07fc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88803b07fc80: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
                                                    ^
 ffff88803b07fd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803b07fd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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