Hello,
syzbot found the following issue on:
HEAD commit: c2603c511feb Linux 6.6.93
git tree: linux-6.6.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=107195d4580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=486bade17c8c30b9
dashboard link:
https://syzkaller.appspot.com/bug?extid=1713e7b02d5c478c5795
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/8754f950a6e7/disk-c2603c51.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/3b19332dbf63/vmlinux-c2603c51.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/cb245e836038/bzImage-c2603c51.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+1713e7...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in rose_get_neigh+0x391/0x990 net/rose/rose_route.c:692
Read of size 1 at addr ffff88805ded6830 by task syz.4.3302/19611
CPU: 0 PID: 19611 Comm: syz.4.3302 Not tainted 6.6.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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/0x230 mm/kasan/report.c:475
kasan_report+0x151/0x180 mm/kasan/report.c:588
rose_get_neigh+0x391/0x990 net/rose/rose_route.c:692
rose_connect+0x417/0x10a0 net/rose/af_rose.c:816
__sys_connect_file net/socket.c:2057 [inline]
__sys_connect+0x397/0x420 net/socket.c:2074
__do_sys_connect net/socket.c:2084 [inline]
__se_sys_connect net/socket.c:2081 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2081
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: 0033:0x7f13ccd8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f13cdc1e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f13ccfb6080 RCX: 00007f13ccd8e929
RDX: 000000000000001c RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007f13cce10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f13ccfb6080 R15: 00007ffdbe77f338
</TASK>
Allocated by task 18835:
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
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
kernfs_fop_open+0x3f5/0xcc0 fs/kernfs/file.c:672
do_dentry_open+0x8c6/0x1500 fs/open.c:929
do_open fs/namei.c:3632 [inline]
path_openat+0x274b/0x3190 fs/namei.c:3789
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
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
Freed by task 18835:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1806 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
slab_free mm/slub.c:3816 [inline]
__kmem_cache_free+0xba/0x1f0 mm/slub.c:3829
kernfs_fop_release+0x166/0x190 fs/kernfs/file.c:810
__fput+0x234/0x970 fs/file_table.c:384
__do_sys_close fs/open.c:1571 [inline]
__se_sys_close+0x15f/0x220 fs/open.c:1556
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:3444
drop_sysctl_table+0x356/0x4b0 fs/proc/proc_sysctl.c:1511
drop_sysctl_table+0x36d/0x4b0 fs/proc/proc_sysctl.c:1514
drop_sysctl_table+0x36d/0x4b0 fs/proc/proc_sysctl.c:1514
unregister_sysctl_table+0x41/0x60 fs/proc/proc_sysctl.c:1532
lowpan_frags_ns_sysctl_unregister net/ieee802154/6lowpan/reassembly.c:407 [inline]
lowpan_frags_exit_net+0x60/0xb0 net/ieee802154/6lowpan/reassembly.c:480
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
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
insert_work+0x3d/0x310 kernel/workqueue.c:1651
__queue_work+0xd2c/0x1020 kernel/workqueue.c:1804
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1746 [inline]
__run_timers+0x558/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
The buggy address belongs to the object at ffff88805ded6800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 48 bytes inside of
freed 512-byte region [ffff88805ded6800, ffff88805ded6a00)
The buggy address belongs to the physical page:
page:ffffea000177b500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5ded4
head:ffffea000177b500 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017841c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 5926, tgid 5926 (syz-executor), ts 113354550038, free_ts 107332147767
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_slab_page+0x5d/0x170 mm/slub.c:1876
allocate_slab mm/slub.c:2023 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2076
___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
__slab_alloc mm/slub.c:3329 [inline]
__slab_alloc_node mm/slub.c:3382 [inline]
slab_alloc_node mm/slub.c:3475 [inline]
__kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc+0xa4/0x240 mm/slab_common.c:1020
kmalloc include/linux/slab.h:604 [inline]
kzalloc include/linux/slab.h:721 [inline]
fib6_info_alloc+0x32/0xe0 net/ipv6/ip6_fib.c:155
ip6_route_info_create+0x44f/0x1200 net/ipv6/route.c:3793
addrconf_f6i_alloc+0x1c6/0x400 net/ipv6/route.c:4621
fixup_permanent_addr net/ipv6/addrconf.c:3561 [inline]
addrconf_permanent_addr+0x275/0x980 net/ipv6/addrconf.c:3600
addrconf_notify+0x996/0x1010 net/ipv6/addrconf.c:3672
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]
__dev_notify_flags+0x18e/0x2e0 net/core/dev.c:-1
dev_change_flags+0xe8/0x1a0 net/core/dev.c:8750
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
__slab_free+0x35e/0x410 mm/slub.c:3722
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
slab_alloc_node mm/slub.c:3485 [inline]
slab_alloc mm/slub.c:3493 [inline]
__kmem_cache_alloc_lru mm/slub.c:3500 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
kmem_cache_zalloc include/linux/slab.h:711 [inline]
alloc_buffer_head+0x2d/0x280 fs/buffer.c:3027
folio_alloc_buffers+0x39b/0x990 fs/buffer.c:935
grow_dev_page fs/buffer.c:1072 [inline]
grow_buffers fs/buffer.c:1118 [inline]
__getblk_slow fs/buffer.c:1145 [inline]
__getblk_gfp+0x2e2/0x660 fs/buffer.c:1439
__getblk include/linux/buffer_head.h:399 [inline]
jbd2_journal_get_descriptor_buffer+0xd1/0x380 fs/jbd2/journal.c:1011
journal_submit_commit_record+0xf5/0x9f0 fs/jbd2/commit.c:129
jbd2_journal_commit_transaction+0x35cd/0x5c30 fs/jbd2/commit.c:882
kjournald2+0x416/0x810 fs/jbd2/journal.c:201
kthread+0x2fa/0x390 kernel/kthread.c:388
Memory state around the buggy address:
ffff88805ded6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88805ded6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805ded6800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88805ded6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805ded6900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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