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

Status: upstream: reported on 2026/09/23 23:13
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+843bf2f48f4d12e6682e@syzkaller.appspotmail.com
First crash: 60d, last: 2d01h
▶ ▼ ✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
d8c84012 repro-c 💥 KASAN: slab-use-after-free Read in __setup_irq 2026/08/15 11:44 2026/08/15 11:44 2026/08/15 18:28 746171ee
ac9b0e08 moderation Actionable: ❌ ❓ KASAN: slab-use-after-free Read in __setup_irq 2026/08/15 00:01 2026/08/15 00:01 2026/08/15 00:03 746171ee
64a25f2f repro-c 💥 KASAN: slab-use-after-free Read in __setup_irq 2026/08/14 15:13 2026/08/14 15:13 2026/08/14 22:52 746171ee
07a59ca5 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Read in __setup_irq 2026/08/12 03:28 2026/08/12 03:28 2026/08/12 04:14 f8d35649
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] serial: core: shut down initialized port on removal 5 (5) 2026/10/03 16:33
[syzbot] [kernel?] KASAN: slab-use-after-free Read in __setup_irq 0 (1) 2026/09/23 23:13
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: slab-use-after-free Read in __setup_irq 19 3 7d19h 17d 0/2 upstream: reported on 2026/09/23 02:54

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x216/0x2d0 lib/vsprintf.c:730
Read of size 1 at addr ffff888026538060 by task syz.1.317/6922

CPU: 0 UID: 0 PID: 6922 Comm: syz.1.317 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x216/0x2d0 lib/vsprintf.c:730
 vsnprintf+0x74a/0xef0 lib/vsprintf.c:2949
 vprintk_store+0x3be/0xd90 kernel/printk/printk.c:2307
 vprintk_emit+0x192/0x560 kernel/printk/printk.c:2455
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 __setup_irq+0x1015/0x2100 kernel/irq/manage.c:1821
 request_threaded_irq+0x2c1/0x3a0 kernel/irq/manage.c:2184
 request_irq include/linux/interrupt.h:176 [inline]
 pcl812_attach+0x254/0x22b0 drivers/comedi/drivers/pcl812.c:1174
 comedi_device_attach+0x52d/0x720 drivers/comedi/drivers.c:1101
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:930 [inline]
 comedi_unlocked_ioctl+0x8ef/0x1af0 drivers/comedi/comedi_fops.c:2302
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f940ef9e199
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f940fe2a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f940f225fa0 RCX: 00007f940ef9e199
RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000004
RBP: 00007f940f0358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f940f226038 R14: 00007f940f225fa0 R15: 00007ffcc6ff5d68
 </TASK>

Allocated by task 6386:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5414 [inline]
 __kmalloc_noprof+0x36b/0x720 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 nsim_fib6_event_init drivers/net/netdevsim/fib.c:810 [inline]
 nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline]
 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline]
 nsim_fib_event_nb+0x283/0x11d0 drivers/net/netdevsim/fib.c:1043
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223
 call_fib_notifiers+0x31/0x60 net/core/fib_notifier.c:36
 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:412 [inline]
 fib6_add_rt2node+0x15f3/0x3940 net/ipv6/ip6_fib.c:1258
 fib6_add+0x9ae/0x1a20 net/ipv6/ip6_fib.c:1535
 __ip6_ins_rt net/ipv6/route.c:1357 [inline]
 ip6_ins_rt+0xd6/0x140 net/ipv6/route.c:1367
 __ipv6_ifa_notify+0x4e8/0xc60 net/ipv6/addrconf.c:6320
 ipv6_ifa_notify net/ipv6/addrconf.c:6359 [inline]
 add_addr+0x1b8/0x2d0 net/ipv6/addrconf.c:3231
 add_v4_addrs+0x571/0x7e0 net/ipv6/addrconf.c:3287
 addrconf_notify+0xb1e/0x1050 net/ipv6/addrconf.c:3776
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline]
 call_netdevice_notifiers net/core/dev.c:2327 [inline]
 __dev_notify_flags+0x31e/0x510 net/core/dev.c:9896
 netif_change_flags+0xde/0x1b0 net/core/dev.c:9925
 do_setlink+0xdd6/0x4670 net/core/rtnetlink.c:3271
 rtnl_changelink net/core/rtnetlink.c:3910 [inline]
 __rtnl_newlink net/core/rtnetlink.c:4081 [inline]
 rtnl_newlink+0x15a3/0x1c30 net/core/rtnetlink.c:4220
 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7137
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2575
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2281
 __do_sys_sendto net/socket.c:2288 [inline]
 __se_sys_sendto net/socket.c:2284 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2284
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5345:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:264 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free mm/slub.c:6509 [inline]
 kfree+0x1c5/0x650 mm/slub.c:6802
 nsim_fib6_event_fini drivers/net/netdevsim/fib.c:842 [inline]
 nsim_fib_event+0x9fd/0xa3a0 drivers/net/netdevsim/fib.c:891
 nsim_fib_event_work+0x244/0x3b0 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888026538060
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
 freed 8-byte region [ffff888026538060, ffff888026538068)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26538
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b041500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 4549598694
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7418
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_node_track_caller_noprof+0x548/0x720 mm/slub.c:5545
 __kmemdup_nul mm/util.c:64 [inline]
 kstrdup+0x42/0x100 mm/util.c:84
 __kernfs_new_node+0xa9/0x980 fs/kernfs/dir.c:661
 kernfs_new_node+0xea/0x140 fs/kernfs/dir.c:751
 kernfs_create_link+0xa7/0x200 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44
 device_add_class_symlinks+0x1cf/0x240 drivers/base/core.c:3520
 device_add+0x467/0xb80 drivers/base/core.c:3712
 tty_register_device_attr+0x428/0x9b0 drivers/tty/tty_io.c:3254
 tty_register_device drivers/tty/tty_io.c:3189 [inline]
 tty_register_driver+0x868/0xe50 drivers/tty/tty_io.c:3469
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888026537f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888026537f80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff888026538000: 05 fc fc fc 05 fc fc fc 05 fc fc fc fa fc fc fc
                                                       ^
 ffff888026538080: 05 fc fc fc fa fc fc fc 00 fc fc fc 05 fc fc fc
 ffff888026538100: 00 fc fc fc fa fc fc fc fa fc fc fc 04 fc fc fc
==================================================================

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/08 07:32 upstream 7b63ef2d55f2 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in __setup_irq
2026/10/08 05:22 upstream 7b63ef2d55f2 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in __setup_irq
2026/10/05 14:29 upstream a90ee4305c4a 1995e6c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in __setup_irq
2026/09/25 02:29 upstream f49a343b305c 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in __setup_irq
2026/09/23 23:12 upstream fe2ec83746e5 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in __setup_irq
2026/09/23 21:03 upstream fe2ec83746e5 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in __setup_irq
2026/09/23 21:03 upstream fe2ec83746e5 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in __setup_irq
2026/08/11 16:14 upstream f5bbbfec59b4 557a89d3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in __setup_irq
2026/08/10 15:09 upstream db2ddb871435 558388e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in __setup_irq
2026/10/03 17:16 linux-next f0406245cb98 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in __setup_irq
2026/10/03 09:02 linux-next f0406245cb98 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: slab-use-after-free Read in __setup_irq
2026/09/28 14:37 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: slab-use-after-free Read in __setup_irq
* Struck through repros no longer work on HEAD.