syzbot

 sign-in | mailing list | source | docs
🐞 Open [679]
🐞 Fixed [61]
🐞 Invalid [698]
⬇ Missing Backports [72]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

KASAN: use-after-free Read in __ext4_iget

Status: upstream: reported on 2024/01/31 03:06
Reported-by: syzbot+caaaafd8611645a190df@syzkaller.appspotmail.com
First crash: 348d, last: 31d
▶ ▼ Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in __ext4_iget 2 123d 165d 0/3 auto-obsoleted due to no activity on 2024/12/21 07:26
upstream KASAN: slab-use-after-free Read in __ext4_iget fs reiserfs 278 349d 586d 0/28 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 177 6h23m 565d 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 453d 497d 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 326d 533d 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 148 2d02h 565d 0/2 premoderation: reported syz repro on 2023/06/28 15:01
android-54 KASAN: use-after-free Read in __ext4_iget (2) 4 208d 226d 0/2 auto-obsoleted due to no activity on 2024/09/17 10:19
linux-6.1 KASAN: slab-out-of-bounds Read in __ext4_iget 14 288d 543d 0/3 auto-obsoleted due to no activity on 2024/07/09 19:10

Sample crash report:
loop1: detected capacity change from 0 to 2048
==================================================================
BUG: KASAN: use-after-free in __ext4_iget+0x2ee/0x3f00 fs/ext4/inode.c:4652
Read of size 8 at addr ffff888074c52060 by task syz.1.6811/19455

CPU: 1 PID: 19455 Comm: syz.1.6811 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 __ext4_iget+0x2ee/0x3f00 fs/ext4/inode.c:4652
 ext4_fill_super+0x7e9d/0xa110 fs/ext4/super.c:4841
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f60e7a3f4ba
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f60e58ade68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f60e58adef0 RCX: 00007f60e7a3f4ba
RDX: 0000000020000780 RSI: 00000000200007c0 RDI: 00007f60e58adeb0
RBP: 0000000020000780 R08: 00007f60e58adef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000200007c0
R13: 00007f60e58adeb0 R14: 0000000000000771 R15: 0000000020000800
 </TASK>

Allocated by task 14157:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
 reiserfs_alloc_inode+0x19/0xb0 fs/reiserfs/super.c:642
 alloc_inode fs/inode.c:236 [inline]
 new_inode_pseudo+0x60/0x210 fs/inode.c:976
 new_inode+0x25/0x1d0 fs/inode.c:1005
 reiserfs_mkdir+0x1bc/0x8f0 fs/reiserfs/namei.c:815
 xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
 create_privroot fs/reiserfs/xattr.c:889 [inline]
 reiserfs_xattr_init+0x348/0x730 fs/reiserfs/xattr.c:1012
 reiserfs_fill_super+0x226a/0x2690 fs/reiserfs/super.c:2179
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Last potentially related work creation:
 kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xba/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3007 [inline]
 call_rcu+0x1c4/0xa70 kernel/rcu/tree.c:3087
 destroy_inode fs/inode.c:291 [inline]
 evict+0x87d/0x930 fs/inode.c:637
 dispose_list fs/inode.c:655 [inline]
 evict_inodes+0x668/0x700 fs/inode.c:709
 generic_shutdown_super+0x94/0x310 fs/super.c:454
 kill_block_super+0x7a/0xe0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Second to last potentially related work creation:
 kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xba/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3007 [inline]
 call_rcu+0x1c4/0xa70 kernel/rcu/tree.c:3087
 destroy_inode fs/inode.c:291 [inline]
 evict+0x87d/0x930 fs/inode.c:637
 dispose_list fs/inode.c:655 [inline]
 evict_inodes+0x668/0x700 fs/inode.c:709
 generic_shutdown_super+0x94/0x310 fs/super.c:454
 kill_block_super+0x7a/0xe0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888074c51a80
 which belongs to the cache reiser_inode_cache of size 1568
The buggy address is located 1504 bytes inside of
 1568-byte region [ffff888074c51a80, ffff888074c520a0)
The buggy address belongs to the page:
page:ffffea0001d31400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888074c53ba0 pfn:0x74c50
head:ffffea0001d31400 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff8880253d6101
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801e5f6000
raw: ffff888074c53ba0 000000008013000b 00000001ffffffff ffff8880253d6101
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5177, ts 69487663729, free_ts 66481621176
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192
 __alloc_pages+0x272/0x700 mm/page_alloc.c:5464
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xbb/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
 reiserfs_alloc_inode+0x19/0xb0 fs/reiserfs/super.c:642
 alloc_inode fs/inode.c:236 [inline]
 iget5_locked+0x9c/0x260 fs/inode.c:1238
 reiserfs_fill_super+0x1140/0x2690 fs/reiserfs/super.c:2057
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
 do_slab_free mm/slub.c:3487 [inline]
 ___cache_free+0xe3/0x100 mm/slub.c:3506
 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 jbd2_alloc_handle include/linux/jbd2.h:1597 [inline]
 new_handle fs/jbd2/transaction.c:477 [inline]
 jbd2__journal_start+0x144/0x5c0 fs/jbd2/transaction.c:504
 __ext4_journal_start_sb+0x175/0x370 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x8b/0x100 fs/ext4/inode.c:6007
 __mark_inode_dirty+0x2fd/0xd60 fs/fs-writeback.c:2464
 generic_update_time+0x1cb/0x1e0 fs/inode.c:1856
 inode_update_time fs/inode.c:1869 [inline]
 file_update_time+0x3eb/0x460 fs/inode.c:2058
 ext4_page_mkwrite+0x1cc/0x1290 fs/ext4/inode.c:6128
 do_page_mkwrite+0x1a9/0x440 mm/memory.c:2920

Memory state around the buggy address:
 ffff888074c51f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888074c51f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888074c52000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888074c52080: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888074c52100: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/13 20:33 linux-5.15.y 0a51d2d4527b 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/08/09 17:18 linux-5.15.y 7e89efd3ae1c a83d9288 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/07/21 09:47 linux-5.15.y 7c6d66f0266f b88348e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/04/12 02:14 linux-5.15.y cdfd0a7f0139 27de0a5c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/04/02 00:09 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/01/31 03:05 linux-5.15.y 6139f2a02fe0 7f400fcb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in __ext4_iget
2024/09/16 14:47 linux-5.15.y 3a5928702e71 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2024/05/30 03:44 linux-5.15.y c61bd26ae81a 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2024/04/02 00:37 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2024/04/01 07:28 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2024/03/29 18:25 linux-5.15.y 9465fef4ae35 c52bcb23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __ext4_iget
2024/10/29 14:09 linux-5.15.y 74cdd62cb470 66aeb999 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in __ext4_iget
2024/07/08 03:47 linux-5.15.y f45bea23c39c 2a40360c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in __ext4_iget
* Struck through repros no longer work on HEAD.