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From: syzbot <syzbot+60332fd095f8bb2946ad@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	netdev@vger.kernel.org,  peterz@infradead.org,
	syzkaller-bugs@googlegroups.com, tglx@kernel.org
Subject: [syzbot] [mm?] KASAN: invalid-free in rcu_free_sheaf
Date: Fri, 12 Jun 2026 13:43:22 -0700	[thread overview]
Message-ID: <6a2c6f6a.be3f099c.2836ae.0004.GAE@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    0ce346bf2f68 Merge branch 'net-shaper-follow-ups-to-recent..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15a50986580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2c40e3284434c6f1
dashboard link: https://syzkaller.appspot.com/bug?extid=60332fd095f8bb2946ad
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fcb2184c91a0/disk-0ce346bf.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/44a7baa2dfdd/vmlinux-0ce346bf.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8ef85b3aefe3/bzImage-0ce346bf.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+60332fd095f8bb2946ad@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: double-free in rcu_free_sheaf+0x31/0x200 mm/slub.c:5850
Free of addr ffff888026c2d380 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:2634 [inline]
 __rcu_free_sheaf_prepare+0x10a/0x2a0 mm/slub.c:2940
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5850
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x389/0x470 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 5613:
 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+0x31c/0x660 mm/slub.c:5420
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 hwsim_update_pib+0x88/0x450 drivers/net/ieee802154/mac802154_hwsim.c:101
 hwsim_set_promiscuous_mode+0x196/0x2e0 drivers/net/ieee802154/mac802154_hwsim.c:323
 drv_set_promiscuous_mode+0x159/0x2e0 net/mac802154/driver-ops.h:127
 drv_start net/mac802154/driver-ops.h:195 [inline]
 mac802154_slave_open net/mac802154/iface.c:196 [inline]
 mac802154_wpan_open+0x19b3/0x2a70 net/mac802154/iface.c:295
 __dev_open+0x44d/0x830 net/core/dev.c:1702
 __dev_change_flags+0x2fa/0x7e0 net/core/dev.c:9752
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9815
 do_setlink+0xfa5/0x45a0 net/core/rtnetlink.c:3207
 rtnl_changelink net/core/rtnetlink.c:3841 [inline]
 __rtnl_newlink net/core/rtnetlink.c:4014 [inline]
 rtnl_newlink+0x15ad/0x1bb0 net/core/rtnetlink.c:4151
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:7068
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2556
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 __sys_sendto+0x672/0x710 net/socket.c:2265
 __do_sys_sendto net/socket.c:2272 [inline]
 __se_sys_sendto net/socket.c:2268 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2268
 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+0x46/0x50 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:2689 [inline]
 __rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:2940
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5850
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x389/0x470 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 ffff888026c2d380
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
 64-byte region [ffff888026c2d380, ffff888026c2d3c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888026c2d780 pfn:0x26c2d
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe1a8c0 ffffea0000d74490 ffffea0001fcda50
raw: ffff888026c2d780 0000000800200010 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 137, tgid 137 (kworker/u8:5), ts 5542876120, free_ts 5542851482
 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+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_node_noprof+0x577/0x7c0 mm/slub.c:5302
 kmalloc_node_noprof include/linux/slab.h:1081 [inline]
 __vmalloc_area_node mm/vmalloc.c:3857 [inline]
 __vmalloc_node_range_noprof+0x5ef/0x1750 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:357 [inline]
 dup_task_struct+0x298/0x840 kernel/fork.c:926
 copy_process+0x89b/0x4440 kernel/fork.c:2090
 kernel_clone+0x2d7/0x940 kernel/fork.c:2722
 user_mode_thread+0x110/0x180 kernel/fork.c:2798
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
page last free pid 137 tgid 137 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1b2/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd47/0x1480 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x36a/0x1750 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:357 [inline]
 dup_task_struct+0x298/0x840 kernel/fork.c:926
 copy_process+0x89b/0x4440 kernel/fork.c:2090
 kernel_clone+0x2d7/0x940 kernel/fork.c:2722
 user_mode_thread+0x110/0x180 kernel/fork.c:2798
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 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

Memory state around the buggy address:
 ffff888026c2d280: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888026c2d300: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888026c2d380: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff888026c2d400: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888026c2d480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


---
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                 reply	other threads:[~2026-06-12 20:43 UTC|newest]

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