==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
Read of size 4 at addr ffff88816cfd6058 by task syz-executor.3/16269

CPU: 1 PID: 16269 Comm: syz-executor.3 Not tainted 5.10.194-syzkaller-00508-ga27512601c2d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x26d/0x6be0 fs/ext4/extents.c:4097
 ext4_map_blocks+0xaa7/0x1ec0 fs/ext4/inode.c:646
 _ext4_get_block+0x21b/0x610 fs/ext4/inode.c:793
 ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:824
 ext4_block_write_begin+0x61e/0x13b0 fs/ext4/inode.c:1077
 ext4_write_begin+0x6fa/0x1730
 ext4_da_write_begin+0x49d/0xf60 fs/ext4/inode.c:3021
 generic_perform_write+0x2cd/0x570 mm/filemap.c:3506
 ext4_buffered_write_iter+0x482/0x610 fs/ext4/file.c:271
 ext4_file_write_iter+0x193/0x1c80 fs/ext4/file.c:685
 do_iter_readv_writev+0x58e/0x790
 do_iter_write+0x183/0x650 fs/read_write.c:866
 vfs_iter_write+0x7c/0xa0 fs/read_write.c:907
 iter_file_splice_write+0x7f1/0xf80 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0xff/0x130 fs/splice.c:933
 splice_direct_to_actor+0x4d1/0xba0 fs/splice.c:888
 do_splice_direct+0x27f/0x3c0 fs/splice.c:976
 do_sendfile+0x8f4/0x10e0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0x1ce/0x230 fs/read_write.c:1304
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7fa742634ae9
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:00007fa738fd60c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fa742754050 RCX: 00007fa742634ae9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000006
RBP: 00007fa74268047a R08: 0000000000000000 R09: 0000000000000000
R10: 0001000000201008 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa742754050 R15: 00007ffe9122f438

The buggy address belongs to the page:
page:ffffea0005b3f580 refcount:1 mapcount:0 mapping:ffff88810c61a698 index:0xcdb pfn:0x16cfd6
aops:ext4_da_aops ino:7c5 dentry name:"file2"
flags: 0x4000000000000016(referenced|uptodate|lru)
raw: 4000000000000016 ffffea0005b3f548 ffffea0005b3f5c8 ffff88810c61a698
raw: 0000000000000cdb 0000000000000000 00000001ffffffff ffff88815f3f2000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88815f3f2000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x112cca(GFP_HIGHUSER_MOVABLE|__GFP_NOWARN|__GFP_NORETRY), pid 16263, ts 867483405054, free_ts 866356483434
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5346
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 __page_cache_alloc include/linux/pagemap.h:290 [inline]
 page_cache_ra_unbounded+0x363/0x890 mm/readahead.c:226
 do_page_cache_ra mm/readahead.c:277 [inline]
 ondemand_readahead+0x863/0xc60 mm/readahead.c:559
 page_cache_async_ra+0x294/0x2d0 mm/readahead.c:617
 page_cache_async_readahead include/linux/pagemap.h:860 [inline]
 generic_file_buffered_read+0x895/0x2aa0 mm/filemap.c:2259
 generic_file_read_iter+0x107/0x6b0 mm/filemap.c:2565
 ext4_file_read_iter+0x287/0x4d0
 call_read_iter include/linux/fs.h:1970 [inline]
 generic_file_splice_read+0x4aa/0x780 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x419/0xba0 fs/splice.c:867
 do_splice_direct+0x27f/0x3c0 fs/splice.c:976
 do_sendfile+0x8f4/0x10e0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0x1ce/0x230 fs/read_write.c:1304
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
 release_pages+0xea0/0xef0 mm/swap.c:1103
 __pagevec_release+0x84/0x100 mm/swap.c:1123
 pagevec_release include/linux/pagevec.h:88 [inline]
 shmem_undo_range+0x7d1/0x1a60 mm/shmem.c:965
 shmem_truncate_range mm/shmem.c:1069 [inline]
 shmem_evict_inode+0x215/0x9d0 mm/shmem.c:1169
 evict+0x2a3/0x6c0 fs/inode.c:577
 iput_final fs/inode.c:1697 [inline]
 iput+0x632/0x7e0 fs/inode.c:1723
 dentry_unlink_inode+0x2e5/0x3d0 fs/dcache.c:374
 __dentry_kill+0x447/0x650 fs/dcache.c:579
 dentry_kill+0xc0/0x2a0
 dput+0x160/0x310 fs/dcache.c:878
 __fput+0x4f4/0x760 fs/file_table.c:294
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x129/0x190 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172

Memory state around the buggy address:
 ffff88816cfd5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816cfd5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816cfd6000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                    ^
 ffff88816cfd6080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816cfd6100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop3): ext4_map_blocks:716: inode #16: block 89391154331688: comm syz-executor.3: lblock 41 mapped to illegal pblock 89391154331688 (length 1)
EXT4-fs error (device loop3) in ext4_reserve_inode_write:5886: Corrupt filesystem
EXT4-fs error (device loop3): ext4_dirty_inode:6096: inode #16: comm syz-executor.3: mark_inode_dirty error
EXT4-fs error (device loop3): ext4_map_blocks:602: inode #16: block 89391154331688: comm syz-executor.3: lblock 41 mapped to illegal pblock 89391154331688 (length 1)
EXT4-fs error (device loop3): ext4_map_blocks:602: inode #16: block 89391154331688: comm syz-executor.3: lblock 41 mapped to illegal pblock 89391154331688 (length 1)
EXT4-fs error (device loop3): ext4_map_blocks:602: inode #16: block 89391154331688: comm syz-executor.3: lblock 41 mapped to illegal pblock 89391154331688 (length 1)
EXT4-fs error (device loop3): ext4_map_blocks:602: inode #16: block 89391154331688: comm syz-executor.3: lblock 41 mapped to illegal pblock 89391154331688 (length 1)
EXT4-fs error (device loop3): ext4_read_block_bitmap_nowait:476: comm syz-executor.3: Invalid block bitmap block 0 in block_group 0
EXT4-fs error (device loop3): ext4_discard_preallocations:4569: comm syz-executor.3: Error -117 reading block bitmap for 0