[Android 5.10] KASAN: use-after-free Read in __ext4_check_dir_entry (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fbe98d68b6b3 ANDROID: GKI: virtual_device: add blk_mq_quie..
git tree: android13-5.10-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11608618580000
kernel config: https://syzkaller.appspot.com/x/.config?x=bb5a3483ded8ee09
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba45d89d357ee2e3c8c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147f51f8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ebe024580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d6f259919514/disk-fbe98d68.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d20d6e4a205a/vmlinux-fbe98d68.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c090817df96c/bzImage-fbe98d68.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/ef0dd4328731/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ba45d...@syzkaller.appspotmail.com

EXT4-fs (loop0): mounted filesystem without journal. Opts: jqfmt=vfsold,data_err=abort,debug,noload,mblk_io_submit,commit=0x0000000000000005,init_itable=0x0000000000000601,debug,,errors=continue
EXT4-fs warning (device loop0): dx_probe:806: inode #2: comm syz-executor385: Unrecognised inode hash code 4
EXT4-fs warning (device loop0): dx_probe:946: inode #2: comm syz-executor385: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
Read of size 2 at addr ffff888121534003 by task syz-executor385/300

CPU: 0 PID: 300 Comm: syz-executor385 Not tainted 5.10.233-syzkaller-00881-gfbe98d68b6b3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307
__ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
ext4_readdir+0x1402/0x37c0 fs/ext4/dir.c:258
iterate_dir+0x265/0x580
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
__x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fea72fffea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff3721ef68 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fea72fffea9
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007fff3721ef9c R09: 00007fff3721ef9c
R10: 00007fff3721ef9c R11: 0000000000000246 R12: 00007fff3721ef9c
R13: 0000000000000002 R14: 431bde82d7b634db R15: 00007fff3721efd0

The buggy address belongs to the page:
page:ffffea0004854d00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x121534
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea000484c508 ffffea000482e108 0000000000000000
raw: 0000000000000001 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x8100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|0x8000000), pid 247, ts 18091564898, free_ts 18151108479
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:5348
__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]
do_anonymous_page mm/memory.c:3963 [inline]
handle_pte_fault+0x175a/0x3e10 mm/memory.c:4786
__handle_mm_fault mm/memory.c:4944 [inline]
handle_mm_fault+0x11d6/0x1a10 mm/memory.c:5358
do_user_addr_fault arch/x86/mm/fault.c:1362 [inline]
handle_page_fault arch/x86/mm/fault.c:1428 [inline]
exc_page_fault+0x2a6/0x5b0 arch/x86/mm/fault.c:1484
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
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
free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:356
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:326
unmap_region+0x31c/0x370 mm/mmap.c:2799
__do_munmap+0x699/0x8c0 mm/mmap.c:3029
__vm_munmap mm/mmap.c:3082 [inline]
__do_sys_munmap mm/mmap.c:3108 [inline]
__se_sys_munmap+0x120/0x1a0 mm/mmap.c:3104
__x64_sys_munmap+0x5b/0x70 mm/mmap.c:3104
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
ffff888121533f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888121533f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888121534000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888121534080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888121534100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 255: comm syz-executor385: path (unknown): bad entry in directory: rec_len is smaller than minimal - offset=1023, inode=0, rec_len=0, size=1024 fake=0


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