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BUG: KASAN: slab-out-of-bounds in sysv_new_block+0x7a7/0xa50 fs/sysv/balloc.c:113
Read of size 4 at addr ffff88802e95e0c8 by task syz-executor.0/7997

CPU: 3 PID: 7997 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller #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
 sysv_new_block+0x7a7/0xa50 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:135 [inline]
 get_block+0x261/0x15a0 fs/sysv/itree.c:254
 __block_write_begin_int+0x4fb/0x16e0 fs/buffer.c:2105
 __block_write_begin fs/buffer.c:2154 [inline]
 block_write_begin+0xb1/0x4a0 fs/buffer.c:2213
 sysv_write_begin+0x31/0xe0 fs/sysv/itree.c:490
 page_symlink+0x3b9/0x440 fs/namei.c:5229
 sysv_symlink+0xd3/0x180 fs/sysv/namei.c:86
 vfs_symlink fs/namei.c:4481 [inline]
 vfs_symlink+0x3e8/0x630 fs/namei.c:4465
 do_symlinkat+0x263/0x310 fs/namei.c:4507
 __do_sys_symlink fs/namei.c:4528 [inline]
 __se_sys_symlink fs/namei.c:4526 [inline]
 __x64_sys_symlink+0x79/0xa0 fs/namei.c:4526
 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
RIP: 0033:0x7ffa0dc7dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffa0e9e40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007ffa0ddabf80 RCX: 00007ffa0dc7dea9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000020000580
RBP: 00007ffa0dcca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007ffa0ddabf80 R15: 00007fffdfa8a368
 </TASK>

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2e940
head: order:5 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000040(head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000040 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
head: 00fff80000000040 0000000000000000 dead000000000122 0000000000000000
head: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
head: 00fff80000000005 ffffea0000ba5001 dead000000000122 00000000ffffffff
head: 0000002000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 5, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 8420, tgid -1156401985 (syz-executor.3), ts 8420, free_ts 211608235671
 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]
 __kmalloc_large_node+0x7f/0x1a0 mm/slub.c:3911
 __do_kmalloc_node mm/slub.c:3954 [inline]
 __kmalloc.cold+0xc/0x61 mm/slub.c:3979
 kmalloc_array include/linux/slab.h:665 [inline]
 kcalloc include/linux/slab.h:696 [inline]
 ieee80211_txq_setup_flows+0x5c1/0xab0 net/mac80211/tx.c:1607
 ieee80211_register_hw+0x2292/0x43b0 net/mac80211/main.c:1497
 mac80211_hwsim_new_radio+0x22ba/0x4e10 drivers/net/wireless/virtual/mac80211_hwsim.c:5454
 hwsim_new_radio_nl+0xaf9/0x1240 drivers/net/wireless/virtual/mac80211_hwsim.c:6135
 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1113
 genl_family_rcv_msg net/netlink/genetlink.c:1193 [inline]
 genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1208
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2559
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1217
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x542/0x820 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x47f/0x4e0 net/socket.c:2191
page last free pid 8115 tgid 8114 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
 __put_partials+0x14c/0x170 mm/slub.c:2906
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 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+0x136/0x320 mm/slub.c:3852
 kmem_cache_zalloc include/linux/slab.h:739 [inline]
 alloc_buffer_head+0x21/0x160 fs/buffer.c:3001
 folio_alloc_buffers+0x2c8/0x7d0 fs/buffer.c:924
 create_empty_buffers+0x36/0x480 fs/buffer.c:1650
 folio_create_buffers+0x109/0x150 fs/buffer.c:1761
 block_read_full_folio+0x20a/0xa70 fs/buffer.c:2365
 filemap_read_folio+0xe7/0x2c0 mm/filemap.c:2331
 do_read_cache_folio+0x207/0x550 mm/filemap.c:3747
 do_read_cache_page mm/filemap.c:3813 [inline]
 read_cache_page+0x5b/0x160 mm/filemap.c:3822
 read_mapping_page include/linux/pagemap.h:888 [inline]
 dir_get_page fs/sysv/dir.c:64 [inline]
 sysv_find_entry+0x1e5/0x690 fs/sysv/dir.c:157

Memory state around the buggy address:
 ffff88802e95df80: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff88802e95e000: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffff88802e95e080: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
                                              ^
 ffff88802e95e100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff88802e95e180: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
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