syzbot


KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree

Status: upstream: reported C repro on 2024/04/14 03:10
Reported-by: syzbot+c15764b4e3c4b99dae18@syzkaller.appspotmail.com
First crash: 70d, last: 55d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree origin:upstream C error 1 55d 70d 0/2 upstream: reported C repro on 2024/04/14 08:35
upstream KMSAN: uninit-value in number (4) kernel C 7189 578d 956d 0/27 closed as invalid on 2022/11/28 10:01
upstream KMSAN: uninit-value in ext4_inlinedir_to_tree ext4 C 267 8d19h 54d 0/27 upstream: reported C repro on 2024/04/29 16:05
android-5-10 KASAN: use-after-free Read in ext4_inlinedir_to_tree C error 1 55d 70d 0/2 upstream: reported C repro on 2024/04/14 03:44
upstream KMSAN: uninit-value in htree_dirblock_to_tree ext4 204 406d 536d 22/27 fixed on 2023/07/01 16:05
Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/04/28 13:23 6m retest repro android12-5.4 report log

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_read_inline_data fs/ext4/inline.c:209 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_inlinedir_to_tree+0x555/0x1160 fs/ext4/inline.c:1399
Read of size 68 at addr ffff8881dbfceec9 by task syz-executor200/356

CPU: 0 PID: 356 Comm: syz-executor200 Not tainted 5.4.268-syzkaller-00012-gd0d34dcb02cc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 check_memory_region_inline mm/kasan/generic.c:141 [inline]
 check_memory_region+0x272/0x280 mm/kasan/generic.c:191
 memcpy+0x25/0x50 mm/kasan/common.c:123
 ext4_read_inline_data fs/ext4/inline.c:209 [inline]
 ext4_inlinedir_to_tree+0x555/0x1160 fs/ext4/inline.c:1399
 ext4_htree_fill_tree+0x5b2/0x1770 fs/ext4/namei.c:1174
 ext4_dx_readdir fs/ext4/dir.c:599 [inline]
 ext4_readdir+0x2c1d/0x3610 fs/ext4/dir.c:142
 iterate_dir+0x266/0x4e0 fs/readdir.c:64
 ksys_getdents64+0x21b/0x4c0 fs/readdir.c:374
 __do_sys_getdents64 fs/readdir.c:395 [inline]
 __se_sys_getdents64 fs/readdir.c:392 [inline]
 __x64_sys_getdents64+0x76/0x80 fs/readdir.c:392
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881dbfceea0
 which belongs to the cache file_lock_cache of size 248
The buggy address is located 41 bytes inside of
 248-byte region [ffff8881dbfceea0, ffff8881dbfcef98)
The buggy address belongs to the page:
page:ffffea00076ff380 refcount:1 mapcount:0 mapping:ffff8881f1dcc780 index:0x0
flags: 0x8000000000000200(slab)
raw: 8000000000000200 dead000000000100 dead000000000122 ffff8881f1dcc780
raw: 0000000000000000 00000000800d000d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4891
 alloc_slab_page+0x39/0x3c0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x440 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2fe/0x490 mm/slub.c:2667
 __slab_alloc+0x62/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x109/0x250 mm/slub.c:2842
 kmem_cache_zalloc include/linux/slab.h:680 [inline]
 locks_alloc_lock fs/locks.c:346 [inline]
 flock_lock_inode+0x342/0x1460 fs/locks.c:1076
 flock_lock_inode_wait fs/locks.c:2162 [inline]
 locks_lock_inode_wait+0xee/0x3f0 fs/locks.c:2189
 locks_lock_file_wait include/linux/fs.h:1375 [inline]
 __do_sys_flock fs/locks.c:2252 [inline]
 __se_sys_flock+0x47b/0x5a0 fs/locks.c:2215
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881dbfced80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881dbfcee00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881dbfcee80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff8881dbfcef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881dbfcef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
EXT4-fs error (device loop0): ext4_inlinedir_to_tree:1437: inode #12: block 7: comm syz-executor200: path /root/syzkaller.zUnyci/0/file0/file0: bad entry in directory: directory entry overrun - offset=34816, inode=2538880996, rec_len=34812, size=128 fake=0
EXT4-fs error (device loop0): empty_inline_dir:1832: inode #12: block 7: comm syz-executor200: bad entry in directory: directory entry overrun - off

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/14 03:09 android12-5.4 d0d34dcb02cc c8349e48 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-android-5-4-kasan KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree
* Struck through repros no longer work on HEAD.