KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree

Status: upstream: reported C repro on 2024/07/21 20:19
Reported-by: syzbot+ed1375847e58c67f38b8@syzkaller.appspotmail.com
First crash: 758d, last: 2d01h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 KASAN: use-after-free Read in ext4_htree_fill_tree missing-backport origin:upstream 19 syz, C error 9 115d 604d 0/2 upstream: reported C repro on 2024/12/22 19:07
android-5-15 KASAN: use-after-free Read in ext4_htree_fill_tree origin:upstream missing-backport 19 syz, C error 9 126d 599d 0/2 upstream: reported C repro on 2024/12/27 19:48
linux-6.1 KASAN: use-after-free Read in ext4_htree_fill_tree 19 1 705d 705d 0/3 auto-obsoleted due to no activity on 2024/12/22 07:44
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/07/31 07:22 1h33m retest repro android13-5.10-lts report log
2026/07/31 07:22 25m retest repro android13-5.10-lts report log
2026/07/31 07:22 1h04m retest repro android13-5.10-lts report log
2026/07/31 07:22 25m retest repro android13-5.10-lts report log
2026/07/31 07:22 23m retest repro android13-5.10-lts report log
2026/07/25 15:33 12m retest repro android13-5.10-lts log
2026/07/25 15:33 13m retest repro android13-5.10-lts log
2026/07/25 15:33 11m retest repro android13-5.10-lts log
2026/07/25 15:33 20m retest repro android13-5.10-lts log
2026/07/25 15:33 26m retest repro android13-5.10-lts log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2026/07/08 20:04 1h13m bisect fix android13-5.10-lts OK (0) job log log
2026/06/07 23:15 1h20m bisect fix android13-5.10-lts OK (0) job log log
2024/09/09 00:15 40m bisect fix android13-5.10-lts OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_htree_fill_tree+0x1080/0x10e0 fs/ext4/namei.c:1221
Read of size 1 at addr ffff88810fdedf7a by task syz-executor/365

CPU: 1 PID: 365 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x100/0x140 mm/kasan/report.c:452
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
 ext4_htree_fill_tree+0x1080/0x10e0 fs/ext4/namei.c:1221
 ext4_dx_readdir fs/ext4/dir.c:601 [inline]
 ext4_readdir+0x2bcf/0x3a80 fs/ext4/dir.c:145
 iterate_dir+0x25c/0x560 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xf2/0x250 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f711c839a73
Code: c7 c0 e8 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb 9e e8 81 9b fd ff 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 e8 ff ff ff f7 d8
RSP: 002b:00007ffdd2ef67e8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000555573d7b910 RCX: 00007f711c839a73
RDX: 0000000000008000 RSI: 0000555573d7b940 RDI: 0000000000000005
RBP: 0000555573d7b940 R08: 0000000000028701 R09: 0000000000000001
R10: 00007f711ca65e20 R11: 0000000000000293 R12: 0000555573d7b914
R13: ffffffffffffffe8 R14: 0000000000000010 R15: 00007ffdd2ef8a90

Allocated by task 365:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 __kmalloc+0x19f/0x330 mm/slub.c:4038
 kmalloc include/linux/slab.h:560 [inline]
 kzalloc include/linux/slab.h:667 [inline]
 fib_create_info+0x8eb/0x1ed0 net/ipv4/fib_semantics.c:1477
 fib_table_insert+0xc2/0x1d50 net/ipv4/fib_trie.c:1170
 fib_magic net/ipv4/fib_frontend.c:1107 [inline]
 fib_add_ifaddr+0x360/0xf90 net/ipv4/fib_frontend.c:1129
 fib_inetaddr_event+0x15d/0x310 net/ipv4/fib_frontend.c:1445
 notifier_call_chain kernel/notifier.c:83 [inline]
 blocking_notifier_call_chain+0xba/0x140 kernel/notifier.c:337
 __inet_insert_ifa+0x88e/0xa80 net/ipv4/devinet.c:567
 inet_rtm_newaddr+0x8cf/0x1580 net/ipv4/devinet.c:967
 rtnetlink_rcv_msg+0x9e9/0xca0 net/core/rtnetlink.c:5622
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5640
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 __sys_sendto+0x467/0x620 net/socket.c:2007
 __do_sys_sendto net/socket.c:2019 [inline]
 __se_sys_sendto net/socket.c:2015 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2015
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff88810fdede00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 122 bytes to the right of
 256-byte region [ffff88810fdede00, ffff88810fdedf00)
The buggy address belongs to the page:
page:ffffea00043f7b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10fdec
head:ffffea00043f7b00 order:1 compound_mapcount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea00043f4480 0000000900000009 ffff888100043200
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 96, ts 4001502013, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x176/0x190 mm/page_alloc.c:2462
 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc_trace+0x1a8/0x2e0 mm/slub.c:2977
 kmalloc include/linux/slab.h:555 [inline]
 inode_doinit_use_xattr+0x5d/0x400 security/selinux/hooks.c:1345
 inode_doinit_with_dentry+0x93a/0xd70 security/selinux/hooks.c:1538
 selinux_d_instantiate+0x27/0x40 security/selinux/hooks.c:6395
 security_d_instantiate+0x9e/0xf0 security/security.c:1980
 d_splice_alias+0x6d/0x390 fs/dcache.c:3038
 kernfs_iop_lookup+0x2c5/0x310 fs/kernfs/dir.c:1178
 lookup_open fs/namei.c:3234 [inline]
 open_last_lookups fs/namei.c:3325 [inline]
 path_openat+0x145d/0x3040 fs/namei.c:3514
 do_filp_open+0x1df/0x400 fs/namei.c:3544
 do_sys_openat2+0x19f/0x750 fs/open.c:1219
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810fdede00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88810fdede80: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
>ffff88810fdedf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88810fdedf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810fdee000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop2): htree_dirblock_to_tree:1092: inode #2: block 33: comm syz-executor: bad entry in directory: inode out of bounds - offset=2012, inode=128, rec_len=36, size=1024 fake=1

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/17 17:42 android13-5.10-lts e334a66065d3 905244d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/12/03 12:18 android13-5.10-lts ab7c0abef9cf 578925bc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/09/27 11:44 android13-5.10-lts 8d23314f588a 9314348a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/07/21 22:17 android13-5.10-lts 1240968f7644 b88348e9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/07/21 20:54 android13-5.10-lts 1240968f7644 b88348e9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/07/21 20:10 android13-5.10-lts 1240968f7644 b88348e9 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2025/01/14 20:35 android13-5.10-lts fbe98d68b6b3 f310a27d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/11/14 13:50 android13-5.10-lts 6a01908517df a8c99394 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/10/31 05:41 android13-5.10-lts e5e5644ea27f 96eb609f .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/09/28 01:34 android13-5.10-lts 8d23314f588a 440b26ec .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/07/21 21:36 android13-5.10-lts 1240968f7644 b88348e9 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/09/27 13:19 android13-5.10-lts 8d23314f588a 9314348a .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2024/09/27 10:29 android13-5.10-lts 8d23314f588a 9314348a .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2025/02/06 15:05 android13-5.10-lts fbe98d68b6b3 577d049b .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2024/07/21 19:23 android13-5.10-lts 1240968f7644 b88348e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: slab-out-of-bounds Read in ext4_htree_fill_tree
2026/08/17 16:44 android13-5.10-lts e334a66065d3 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2026/08/17 16:43 android13-5.10-lts e334a66065d3 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
2026/08/17 16:43 android13-5.10-lts e334a66065d3 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in ext4_htree_fill_tree
* Struck through repros no longer work on HEAD.