syzbot


KASAN: slab-use-after-free Read in rose_new_lci

Status: upstream: reported syz repro on 2025/07/24 09:38
Subsystems: hams
[Documentation on labels]
Reported-by: syzbot+0fc08dad8f34563208d5@syzkaller.appspotmail.com
First crash: 30d, last: 27d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [hams?] KASAN: slab-use-after-free Read in rose_new_lci 3 (7) 2025/07/25 01:07
Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/08/07 14:43 23m retest repro linux-next OK log
2025/07/25 00:42 23m hdanton@sina.com patch linux-next OK log
2025/07/24 23:22 23m hdanton@sina.com patch linux-next error
2025/07/24 14:19 2h25m hdanton@sina.com patch linux-next error

Sample crash report:
bpq0: left promiscuous mode
bpq0: left allmulticast mode
==================================================================
BUG: KASAN: slab-use-after-free in rose_new_lci+0x130/0x140 net/rose/af_rose.c:325
Read of size 1 at addr ffff88802b4ff431 by task syz.3.160/6574

CPU: 1 UID: 0 PID: 6574 Comm: syz.3.160 Not tainted 6.16.0-rc6-syzkaller-00279-gbf61759db409 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x610 mm/kasan/report.c:480
 kasan_report+0xe0/0x110 mm/kasan/report.c:593
 rose_new_lci+0x130/0x140 net/rose/af_rose.c:325
 rose_connect+0x317/0x1540 net/rose/af_rose.c:823
 __sys_connect_file+0x13e/0x1a0 net/socket.c:2038
 __sys_connect+0x13b/0x160 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f061698e9a9
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:00007f0617824038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f0616bb5fa0 RCX: 00007f061698e9a9
RDX: 0000000000000040 RSI: 0000200000000100 RDI: 000000000000000d
RBP: 00007f0616a10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0616bb5fa0 R15: 00007ffdf2b7ebe8
 </TASK>

Allocated by task 6268:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 rose_add_node net/rose/rose_route.c:85 [inline]
 rose_rt_ioctl+0x87e/0x1d40 net/rose/rose_route.c:740
 rose_ioctl+0x64d/0x7d0 net/rose/af_rose.c:1380
 sock_do_ioctl+0x118/0x280 net/socket.c:1190
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6579:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 rose_remove_neigh+0x25e/0x370 net/rose/rose_route.c:240
 rose_rt_device_down+0x2dc/0x430 net/rose/rose_route.c:515
 rose_device_event+0xfc/0x120 net/rose/af_rose.c:248
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x1f7/0x2e0 net/core/dev.c:9499
 netif_change_flags+0x108/0x160 net/core/dev.c:9526
 dev_change_flags+0xba/0x250 net/core/dev_api.c:68
 dev_ifsioc+0x1498/0x1f70 net/core/dev_ioctl.c:565
 dev_ioctl+0x223/0x10e0 net/core/dev_ioctl.c:823
 sock_do_ioctl+0x19d/0x280 net/socket.c:1204
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b4ff400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 49 bytes inside of
 freed 512-byte region [ffff88802b4ff400, ffff88802b4ff600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802b4fe400 pfn:0x2b4fc
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801b841c80 ffffea00015a2310 ffffea00015bc910
raw: ffff88802b4fe400 000000000010000f 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b841c80 ffffea00015a2310 ffffea00015bc910
head: ffff88802b4fe400 000000000010000f 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000ad3f01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5221, tgid 5221 (udevadm), ts 27546529743, free_ts 25503706164
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4354
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 kernfs_fop_open+0x244/0xda0 fs/kernfs/file.c:623
 do_dentry_open+0x744/0x1c10 fs/open.c:964
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:3896 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4055
 do_filp_open+0x20b/0x470 fs/namei.c:4082
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
page last free pid 5216 tgid 5216 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3186
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204
 getname_flags.part.0+0x4c/0x550 fs/namei.c:146
 getname_flags+0x93/0xf0 include/linux/audit.h:322
 getname include/linux/fs.h:2907 [inline]
 do_sys_openat2+0xb8/0x1d0 fs/open.c:1431
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802b4ff300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b4ff380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b4ff400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88802b4ff480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b4ff500: 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
2025/07/20 09:33 upstream bf61759db409 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in rose_new_lci
2025/07/23 00:52 linux-next d086c886ceb9 85deaf45 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: slab-use-after-free Read in rose_new_lci
* Struck through repros no longer work on HEAD.