EXT4-fs error (device loop5): ext4_mb_release_inode_pa:4375: group 0, 
free 0, pa_free 1
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BUG: KASAN: use-after-free in ext4_ext_try_to_merge_right+0x416/0x820 fs/ext4/extents.c:1819
Read of size 718380 at addr ffff8881165bb5f8 by task syz.5.332/1782

CPU: 0 PID: 1782 Comm: syz.5.332 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 ext4_ext_try_to_merge_right+0x416/0x820 fs/ext4/extents.c:1819
 ext4_ext_shift_path_extents fs/ext4/extents.c:5125 [inline]
 ext4_ext_shift_extents+0xd24/0x14a0 fs/ext4/extents.c:5302
 ext4_collapse_range fs/ext4/extents.c:5436 [inline]
 ext4_fallocate+0x109c/0x1a70 fs/ext4/extents.c:4769
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 ksys_fallocate fs/open.c:333 [inline]
 __do_sys_fallocate fs/open.c:341 [inline]
 __se_sys_fallocate fs/open.c:339 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:339
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc090494819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc08eeef028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fc09070dfa0 RCX: 00007fc090494819
RDX: 0000000000004000 RSI: 0000000000000008 RDI: 0000000000000009
RBP: 00007fc09052ac91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc09070e038 R14: 00007fc09070dfa0 R15: 00007ffd5a535408

The buggy address belongs to the page:
page:ffffea0004596ec0 refcount:2 mapcount:0 mapping:ffff8881107479d0 index:0x20 pfn:0x1165bb
aops:def_blk_aops ino:0
flags: 0x400000000002203e(referenced|uptodate|dirty|lru|active|private|mappedtodisk)
raw: 400000000002203e ffffea000445b708 ffffea00049a0348 ffff8881107479d0
raw: 0000000000000020 ffff88812bccc738 00000002ffffffff ffff888100142000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888100142000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 312, ts 100207791405, free_ts 100101223456
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x223b/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5384
 __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+0x2dc/0x7e0 mm/readahead.c:226
 do_page_cache_ra mm/readahead.c:277 [inline]
 force_page_cache_ra+0x3a9/0x400 mm/readahead.c:308
 page_cache_sync_ra+0x237/0x2a0 mm/readahead.c:582
 page_cache_sync_readahead include/linux/pagemap.h:837 [inline]
 generic_file_buffered_read+0x574/0x2770 mm/filemap.c:2250
 generic_file_read_iter+0x11e/0x5c0 mm/filemap.c:2568
 blkdev_read_iter+0x12f/0x160 fs/block_dev.c:1956
 call_read_iter include/linux/fs.h:2060 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x62a/0xa60 fs/read_write.c:496
 ksys_read+0x149/0x250 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:642
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
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+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page mm/page_alloc.c:3391 [inline]
 free_the_page mm/page_alloc.c:5443 [inline]
 __free_pages+0x146/0x3b0 mm/page_alloc.c:5454
 __vunmap+0x86d/0x9f0 mm/vmalloc.c:2307
 __vfree mm/vmalloc.c:2356 [inline]
 vfree+0x61/0x90 mm/vmalloc.c:2387
 bpf_prog_calc_tag+0x5ec/0x720 kernel/bpf/core.c:343
 resolve_pseudo_ldimm64+0xcc/0x1060 kernel/bpf/verifier.c:10570
 bpf_check+0x9058/0xdb10 kernel/bpf/verifier.c:12663
 bpf_prog_load+0xfca/0x14a0 kernel/bpf/syscall.c:2234
 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline]
 __se_sys_bpf+0x49a/0x740 kernel/bpf/syscall.c:4391
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff8881165bbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881165bbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881165bc000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8881165bc080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
 ffff8881165bc100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
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