syzbot


KMSAN: uninit-value in decay_va_pool_node

Status: upstream: reported on 2026/04/02 05:31
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+37b7f6cd519f7fb8d32a@syzkaller.appspotmail.com
First crash: 6d05h, last: 6d05h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] mm/vmalloc: fix KMSAN uninit-value warning in decay_va_pool_node() 10 (10) 2026/04/03 17:22
[syzbot] [kernel?] KMSAN: uninit-value in decay_va_pool_node 0 (1) 2026/04/02 05:31

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in __list_del_entry_valid include/linux/list.h:-1 [inline]
BUG: KMSAN: uninit-value in __list_del_entry include/linux/list.h:223 [inline]
BUG: KMSAN: uninit-value in list_del_init include/linux/list.h:295 [inline]
BUG: KMSAN: uninit-value in decay_va_pool_node+0xf78/0x1dd0 mm/vmalloc.c:2255
 __list_del_entry_valid include/linux/list.h:-1 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del_init include/linux/list.h:295 [inline]
 decay_va_pool_node+0xf78/0x1dd0 mm/vmalloc.c:2255
 __purge_vmap_area_lazy+0x1a1/0x1500 mm/vmalloc.c:2361
 _vm_unmap_aliases+0x134c/0x1490 mm/vmalloc.c:2996
 vm_reset_perms+0x625/0x900 mm/vmalloc.c:3388
 vfree+0x463/0xa10 mm/vmalloc.c:3467
 bpf_prog_free_deferred+0xc12/0xc80 kernel/bpf/core.c:-1
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb82/0x1e80 kernel/workqueue.c:3359
 worker_thread+0xee4/0x1590 kernel/workqueue.c:3440
 kthread+0x53f/0x600 kernel/kthread.c:436
 ret_from_fork+0x20f/0x910 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 __list_del_entry_valid include/linux/list.h:127 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del_init include/linux/list.h:295 [inline]
 decay_va_pool_node+0xf71/0x1dd0 mm/vmalloc.c:2255
 __purge_vmap_area_lazy+0x1a1/0x1500 mm/vmalloc.c:2361
 _vm_unmap_aliases+0x134c/0x1490 mm/vmalloc.c:2996
 vm_reset_perms+0x625/0x900 mm/vmalloc.c:3388
 vfree+0x463/0xa10 mm/vmalloc.c:3467
 bpf_prog_free_deferred+0xc12/0xc80 kernel/bpf/core.c:-1
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb82/0x1e80 kernel/workqueue.c:3359
 worker_thread+0xee4/0x1590 kernel/workqueue.c:3440
 kthread+0x53f/0x600 kernel/kthread.c:436
 ret_from_fork+0x20f/0x910 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4545 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_node_noprof+0x3cd/0x12d0 mm/slub.c:4918
 alloc_vmap_area+0x327/0x2e30 mm/vmalloc.c:2065
 __get_vm_area_node+0x263/0x3b0 mm/vmalloc.c:3232
 __vmalloc_node_range_noprof+0x44a/0x2d80 mm/vmalloc.c:4024
 __vmalloc_node_noprof mm/vmalloc.c:4124 [inline]
 vzalloc_noprof+0xce/0x140 mm/vmalloc.c:4202
 alloc_counters+0x7c/0x8a0 net/ipv4/netfilter/ip_tables.c:799
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
 do_ip6t_get_ctl+0xab1/0x1fc0 net/ipv6/netfilter/ip6_tables.c:1677
 nf_getsockopt+0x497/0x4f0 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x323/0x4c0 net/ipv6/ipv6_sockglue.c:1473
 tcp_getsockopt+0x174/0x1a0 net/ipv4/tcp.c:4894
 sock_common_getsockopt+0x9c/0xf0 net/core/sock.c:3946
 do_sock_getsockopt+0x3a8/0x4c0 net/socket.c:2383
 __sys_getsockopt net/socket.c:2412 [inline]
 __do_sys_getsockopt net/socket.c:2419 [inline]
 __se_sys_getsockopt net/socket.c:2416 [inline]
 __x64_sys_getsockopt+0x32d/0x520 net/socket.c:2416
 x64_sys_call+0x3ab8/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:56
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 7227 Comm: kworker/0:8 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events bpf_prog_free_deferred

=====================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/29 05:24 upstream be762d8b6dd7 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in decay_va_pool_node
* Struck through repros no longer work on HEAD.