syzbot


KASAN: invalid-free in rcu_free_sheaf

Status: upstream: reported on 2026/06/12 20:43
Subsystems: mm arm net
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+60332fd095f8bb2946ad@syzkaller.appspotmail.com
First crash: 32d, last: 19d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
fb1c2244-7846-4925-aea2-4d5887261b5c assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KASAN: invalid-free in rcu_free_sheaf 2026/06/10 06:10 2026/06/10 06:10 2026/06/10 06:52 34dab4be5c118c76aea929f2aa0c188548615110

			
		
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] ieee802154: hwsim: serialize pib updates to fix double-free 1 (1) 2026/07/09 22:18
[syzbot] [mm?] KASAN: invalid-free in rcu_free_sheaf 0 (1) 2026/06/12 20:43

Sample crash report:
==================================================================
BUG: KASAN: double-free in rcu_free_sheaf+0x31/0x200 mm/slub.c:5909
Free of addr ffff888078aaec00 by task ksoftirqd/0/15

CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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_invalid_free+0xea/0x110 mm/kasan/report.c:557
 check_slab_allocation mm/kasan/common.c:-1 [inline]
 __kasan_slab_pre_free+0x104/0x120 mm/kasan/common.c:261
 kasan_slab_pre_free include/linux/kasan.h:199 [inline]
 slab_free_hook mm/slub.c:2645 [inline]
 __rcu_free_sheaf_prepare+0x10a/0x2a0 mm/slub.c:2951
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5909
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 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
 </TASK>

Allocated by task 27097:
 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:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 hwsim_update_pib+0x88/0x450 drivers/net/ieee802154/mac802154_hwsim.c:101
 hwsim_hw_channel+0x178/0x2b0 drivers/net/ieee802154/mac802154_hwsim.c:128
 drv_set_channel net/mac802154/driver-ops.h:240 [inline]
 ieee802154_set_channel+0x292/0x530 net/mac802154/cfg.c:121
 rdev_set_channel net/ieee802154/rdev-ops.h:81 [inline]
 nl802154_set_channel+0x24d/0x420 net/ieee802154/nl802154.c:989
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x9b9/0xa20 net/socket.c:2684
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 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:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2700 [inline]
 __rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:2951
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5909
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 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 ffff888078aaec00
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
 64-byte region [ffff888078aaec00, ffff888078aaec40)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78aae
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fe1b8c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 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 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4995, tgid 4995 (udevd), ts 26975453585, free_ts 23459458262
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_noprof+0x464/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x5fa/0x640 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776
 security_file_open+0xa9/0x240 security/security.c:2739
 do_dentry_open+0x4a0/0x1380 fs/open.c:924
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4700 [inline]
 path_openat+0x2e44/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __free_pages mm/page_alloc.c:5340 [inline]
 free_contig_range+0xb7/0x100 mm/page_alloc.c:7308
 destroy_args+0x4e5/0x570 mm/debug_vm_pgtable.c:993
 debug_vm_pgtable+0x3f8/0x410 mm/debug_vm_pgtable.c:1368
 do_one_initcall+0x250/0x870 init/main.c:1347
 do_initcall_level+0x10a/0x1a0 init/main.c:1409
 do_initcalls+0x59/0xa0 init/main.c:1425
 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658
 kernel_init+0x1d/0x1d0 init/main.c:1548
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888078aaeb00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888078aaeb80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff888078aaec00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff888078aaec80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888078aaed00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/22 03:06 net 1579342d7113 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce KASAN: invalid-free in rcu_free_sheaf
2026/06/17 03:25 net-next 72dfa4700f78 0e4b3e40 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce KASAN: invalid-free in rcu_free_sheaf
2026/06/11 22:03 net-next 0ce346bf2f68 d93a6ab6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce KASAN: invalid-free in rcu_free_sheaf
2026/06/08 20:36 net-next 903db046d557 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce KASAN: invalid-free in rcu_free_sheaf
2026/06/12 02:46 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 596d152bc5e3 e93da63e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: invalid-free in rcu_free_sheaf
* Struck through repros no longer work on HEAD.