syzbot


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

Status: upstream: reported on 2025/09/25 10:35
Reported-by: syzbot+8a0ce79f5ba7dc0aaa07@syzkaller.appspotmail.com
First crash: 63d, last: 36d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: slab-out-of-bounds Read in reiserfs_xattr_get (2) 17 3 40d 104d 0/3 upstream: reported on 2025/08/15 02:35
linux-6.1 KASAN: slab-out-of-bounds Read in reiserfs_xattr_get 17 1 342d 342d 0/3 auto-obsoleted due to no activity on 2025/03/30 06:16
linux-5.15 KASAN: slab-out-of-bounds Read in reiserfs_xattr_get 17 3 225d 298d 0/3 auto-obsoleted due to no activity on 2025/07/24 22:48
upstream KASAN: slab-out-of-bounds Read in reiserfs_xattr_get (2) fs 17 1 668d 664d 0/29 auto-obsoleted due to no activity on 2024/05/07 19:35
upstream KASAN: slab-out-of-bounds Read in reiserfs_xattr_get fs 19 106 803d 1689d 0/29 auto-obsoleted due to no activity on 2023/12/25 15:39

Sample crash report:
loop2: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in reiserfs_xattr_get+0xfe/0x5a0 fs/reiserfs/xattr.c:676
Read of size 8 at addr ffff88802aa10598 by task syz.2.6460/20690

CPU: 0 PID: 20690 Comm: syz.2.6460 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 reiserfs_xattr_get+0xfe/0x5a0 fs/reiserfs/xattr.c:676
 reiserfs_get_acl+0x7e/0x6a0 fs/reiserfs/xattr_acl.c:215
 __get_acl+0x26d/0x3f0 fs/posix_acl.c:160
 check_acl+0x3a/0x150 fs/namei.c:310
 acl_permission_check fs/namei.c:355 [inline]
 generic_permission+0x381/0x590 fs/namei.c:408
 do_inode_permission fs/namei.c:462 [inline]
 inode_permission+0x23d/0x480 fs/namei.c:529
 may_open+0x2e9/0x440 fs/namei.c:3268
 do_open fs/namei.c:3638 [inline]
 path_openat+0x25e4/0x3190 fs/namei.c:3797
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7b9db8d810
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 69 95 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 bc 95 02 00 8b 44
RSP: 002b:00007f7b9e9ecdf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f7b9db8d810
RDX: 0000000000010000 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 0000200000000040 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000293 R12: 0000200000000040
R13: 00007f7b9e9eceb0 R14: 000000000000612b R15: 0000200000008800
 </TASK>

Allocated by task 20690:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xb4/0x240 mm/slab_common.c:1020
 kmalloc_array include/linux/slab.h:637 [inline]
 kcalloc include/linux/slab.h:668 [inline]
 __list_lru_init+0xa6/0x5f0 mm/list_lru.c:571
 alloc_super+0x74a/0x920 fs/super.c:393
 sget+0x1ce/0x4d0 fs/super.c:897
 mount_bdev+0xec/0x2d0 fs/super.c:1623
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 kvfree_call_rcu+0xee/0x780 kernel/rcu/tree.c:3452
 drop_sysctl_table+0x356/0x4b0 fs/proc/proc_sysctl.c:1515
 drop_sysctl_table+0x36d/0x4b0 fs/proc/proc_sysctl.c:1518
 unregister_sysctl_table+0x41/0x60 fs/proc/proc_sysctl.c:1536
 neigh_sysctl_unregister+0x78/0xa0 net/core/neighbour.c:3891
 devinet_sysctl_unregister net/ipv4/devinet.c:2685 [inline]
 inetdev_destroy net/ipv4/devinet.c:330 [inline]
 inetdev_event+0x7b8/0x15c0 net/ipv4/devinet.c:1636
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0xf36/0x1810 net/core/dev.c:11086
 ip_tunnel_delete_nets+0x31c/0x360 net/ipv4/ip_tunnel.c:1171
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x77f/0xb90 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 kvfree_call_rcu+0xee/0x780 kernel/rcu/tree.c:3452
 drop_sysctl_table+0x356/0x4b0 fs/proc/proc_sysctl.c:1515
 drop_sysctl_table+0x36d/0x4b0 fs/proc/proc_sysctl.c:1518
 unregister_sysctl_table+0x41/0x60 fs/proc/proc_sysctl.c:1536
 mptcp_pernet_del_table net/mptcp/ctrl.c:223 [inline]
 mptcp_net_exit+0x5d/0x70 net/mptcp/ctrl.c:253
 ops_exit_list net/core/net_namespace.c:173 [inline]
 cleanup_net+0x6f4/0xb90 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff88802aa10400
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 152 bytes to the right of
 allocated 256-byte region [ffff88802aa10400, ffff88802aa10500)

The buggy address belongs to the physical page:
page:ffffea0000aa8400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2aa10
head:ffffea0000aa8400 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017841b40 ffffea0001d86b00 dead000000000006
raw: 0000000000000000 0000000080100010 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 20056235612, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node+0xa4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kvmalloc_node+0x70/0x180 mm/util.c:617
 kvmalloc include/linux/slab.h:738 [inline]
 kvzalloc include/linux/slab.h:746 [inline]
 v4l2_ctrl_new+0x9ff/0x1720 drivers/media/v4l2-core/v4l2-ctrls-core.c:1926
 v4l2_ctrl_new_std+0x24a/0x2f0 drivers/media/v4l2-core/v4l2-ctrls-core.c:2063
 handler_new_ref+0x153/0x9c0 drivers/media/v4l2-core/v4l2-ctrls-core.c:1684
 v4l2_ctrl_add_handler+0x19b/0x290 drivers/media/v4l2-core/v4l2-ctrls-core.c:2207
 vivid_create_controls+0x252d/0x3430 drivers/media/test-drivers/vivid/vivid-ctrls.c:1943
 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1840 [inline]
 vivid_probe+0x3824/0x5ce0 drivers/media/test-drivers/vivid/vivid-core.c:2004
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802aa10480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802aa10500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802aa10580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                            ^
 ffff88802aa10600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802aa10680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/22 03:21 linux-6.6.y f231f248323d 252fbbad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in reiserfs_xattr_get
2025/09/25 10:34 linux-6.6.y 147338df3487 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in reiserfs_xattr_get
* Struck through repros no longer work on HEAD.