=====================================================
BUG: KMSAN: uninit-value in __preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
BUG: KMSAN: uninit-value in preempt_count_add+0x1b5/0x320 kernel/sched/core.c:5532
 __preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
 preempt_count_add+0x1b5/0x320 kernel/sched/core.c:5532
 sysvec_reschedule_ipi+0x1c/0x110 arch/x86/kernel/smp.c:225
 asm_sysvec_reschedule_ipi+0x12/0x20
 smap_save mm/kmsan/instrumentation.c:76 [inline]
 get_shadow_origin_ptr mm/kmsan/instrumentation.c:32 [inline]
 __msan_metadata_ptr_for_load_4+0x10/0x30 mm/kmsan/instrumentation.c:76
 ip_fast_csum+0x2b0/0x5b0 lib/checksum.c:108
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:765 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:799 [inline]
 nsim_dev_trap_report_work+0x8e5/0x11a0 drivers/net/netdevsim/dev.c:840
 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2289
 worker_thread+0x10d0/0x2240 kernel/workqueue.c:2436
 kthread+0x3c7/0x500 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:754 [inline]
 slab_alloc_node mm/slub.c:3231 [inline]
 __kmalloc_node_track_caller+0xde3/0x14f0 mm/slub.c:4962
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1300 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:742 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:799 [inline]
 nsim_dev_trap_report_work+0x3da/0x11a0 drivers/net/netdevsim/dev.c:840
 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2289
 worker_thread+0x10d0/0x2240 kernel/workqueue.c:2436
 kthread+0x3c7/0x500 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

CPU: 0 PID: 3558 Comm: kworker/0:3 Not tainted 5.18.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
=====================================================