syzbot


KASAN: slab-out-of-bounds Read in __ext4_iget

Status: upstream: reported on 2023/07/19 22:47
Reported-by: syzbot+a5b7a444d322fed7e980@syzkaller.appspotmail.com
First crash: 341d, last: 85d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in __ext4_iget fs reiserfs 278 146d 383d 0/27 auto-obsoleted due to no activity on 2024/04/09 13:42
android-5-15 KASAN: use-after-free Read in __ext4_iget origin:lts syz 57 3d08h 362d 0/2 premoderation: reported syz repro on 2023/06/28 10:27
linux-5.15 KASAN: slab-out-of-bounds Read in __ext4_iget 6 251d 294d 0/3 auto-obsoleted due to no activity on 2024/01/25 22:09
android-54 KASAN: use-after-free Read in __ext4_iget 13 123d 330d 0/2 auto-obsoleted due to no activity on 2024/05/22 19:07
android-5-10 KASAN: use-after-free Read in __ext4_iget syz 83 2d12h 362d 0/2 premoderation: reported syz repro on 2023/06/28 15:01
linux-5.15 KASAN: use-after-free Read in __ext4_iget 7 25d 145d 0/3 upstream: reported on 2024/01/31 03:06

Sample crash report:
loop4: detected capacity change from 0 to 512
==================================================================
BUG: KASAN: slab-out-of-bounds in __ext4_iget+0x254/0x31b4 fs/ext4/inode.c:4824
Read of size 8 at addr ffff0000d71dff30 by task syz-executor.4/15102

CPU: 1 PID: 15102 Comm: syz-executor.4 Not tainted 6.1.68-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:395
 kasan_report+0xd4/0x130 mm/kasan/report.c:495
 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
 __ext4_iget+0x254/0x31b4 fs/ext4/inode.c:4824
 __ext4_fill_super fs/ext4/super.c:5399 [inline]
 ext4_fill_super+0x5a44/0x7570 fs/ext4/super.c:5664
 get_tree_bdev+0x360/0x54c fs/super.c:1355
 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5694
 vfs_get_tree+0x90/0x274 fs/super.c:1562
 do_new_mount+0x25c/0x8c4 fs/namespace.c:3040
 path_mount+0x590/0xe5c fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3568
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4271:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x458 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc_lru+0x1ac/0x2f8 mm/slub.c:3429
 alloc_inode_sb include/linux/fs.h:3176 [inline]
 sock_alloc_inode+0x2c/0xcc net/socket.c:304
 alloc_inode fs/inode.c:259 [inline]
 new_inode_pseudo+0x68/0x1d0 fs/inode.c:1018
 sock_alloc net/socket.c:629 [inline]
 __sock_create+0x134/0x884 net/socket.c:1501
 sock_create net/socket.c:1588 [inline]
 __sys_socket_create net/socket.c:1625 [inline]
 __sys_socket+0x120/0x32c net/socket.c:1653
 __do_sys_socket net/socket.c:1666 [inline]
 __se_sys_socket net/socket.c:1664 [inline]
 __arm64_sys_socket+0x7c/0x94 net/socket.c:1664
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Freed by task 21:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x144/0x1c0 mm/kasan/common.c:236
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:244
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook mm/slub.c:1750 [inline]
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0x2f0/0x588 mm/slub.c:3683
 sock_free_inode+0x28/0x38 net/socket.c:325
 i_callback+0x50/0x78 fs/inode.c:248
 rcu_do_batch kernel/rcu/tree.c:2264 [inline]
 rcu_core+0x878/0x1c10 kernel/rcu/tree.c:2524
 rcu_core_si+0x10/0x1c kernel/rcu/tree.c:2541
 __do_softirq+0x314/0xe38 kernel/softirq.c:571

Last potentially related work creation:
 kasan_save_stack+0x40/0x70 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
 call_rcu+0xfc/0xa40 kernel/rcu/tree.c:2812
 destroy_inode fs/inode.c:314 [inline]
 evict+0x5fc/0x68c fs/inode.c:679
 iput_final fs/inode.c:1789 [inline]
 iput+0x7c0/0x8a4 fs/inode.c:1815
 dentry_unlink_inode+0x370/0x4b0 fs/dcache.c:401
 __dentry_kill+0x324/0x5e4 fs/dcache.c:607
 dentry_kill+0xc8/0x250
 dput+0x218/0x454 fs/dcache.c:913
 __fput+0x4f4/0x7bc fs/file_table.c:328
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x240/0x2f0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2148/0x3474 arch/arm64/kernel/signal.c:1132
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Second to last potentially related work creation:
 kasan_save_stack+0x40/0x70 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
 call_rcu+0xfc/0xa40 kernel/rcu/tree.c:2812
 destroy_inode fs/inode.c:314 [inline]
 evict+0x5fc/0x68c fs/inode.c:679
 iput_final fs/inode.c:1789 [inline]
 iput+0x7c0/0x8a4 fs/inode.c:1815
 dentry_unlink_inode+0x370/0x4b0 fs/dcache.c:401
 __dentry_kill+0x324/0x5e4 fs/dcache.c:607
 dentry_kill+0xc8/0x250
 dput+0x218/0x454 fs/dcache.c:913
 __fput+0x4f4/0x7bc fs/file_table.c:328
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x240/0x2f0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2148/0x3474 arch/arm64/kernel/signal.c:1132
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d71df800
 which belongs to the cache sock_inode_cache of size 1408
The buggy address is located 432 bytes to the right of
 1408-byte region [ffff0000d71df800, ffff0000d71dfd80)

The buggy address belongs to the physical page:
page:00000000da59c98e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1171d8
head:00000000da59c98e order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff0000d2d1fc01
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0b6ca80
raw: 0000000000000000 0000000000150015 00000001ffffffff ffff0000d2d1fc01
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d71dfe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d71dfe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d71dff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff0000d71dff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d71e0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs (loop4): corrupt root inode, run e2fsck
EXT4-fs (loop4): mount failed

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/19 22:38 linux-6.1.y ba6f5fb46511 3ad490ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in __ext4_iget
2023/10/05 22:47 linux-6.1.y d23900f974e0 db17ad9f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in __ext4_iget
2023/07/19 22:46 linux-6.1.y a456e1743881 4547cdf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in __ext4_iget
2024/03/31 19:09 linux-6.1.y e5cd595e23c1 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2023/12/26 09:47 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2023/12/18 21:37 linux-6.1.y ba6f5fb46511 924661f4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2023/11/06 05:12 linux-6.1.y 4a61839152cc 500bfdc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2023/10/24 08:35 linux-6.1.y 7d24402875c7 af8d2e46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2024/02/01 02:33 linux-6.1.y e5c3b988b827 373b66cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2023/12/30 03:59 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2023/12/25 23:21 linux-6.1.y 4aa6747d9352 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2023/09/25 06:32 linux-6.1.y d23900f974e0 0b6a67ac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2023/08/05 09:40 linux-6.1.y 52a953d0934b cdae481e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
2023/07/22 15:51 linux-6.1.y a456e1743881 27cbe77f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in __ext4_iget
* Struck through repros no longer work on HEAD.