Re: [syzbot] [hfs?] KMSAN: uninit-value in hfsplus_bnode_find

syzbot
2026-04-17T19:31:02Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt

=====================================================
BUG: KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt+0xb0/0xc0 include/linux/irq-entry-common.h:472
irqentry_exit_to_kernel_mode_preempt+0xb0/0xc0 include/linux/irq-entry-common.h:472
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
irqentry_exit+0x7b/0x760 kernel/entry/common.c:164
sysvec_apic_timer_interrupt+0x52/0x90 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:697
__sanitizer_cov_trace_pc+0x0/0x70
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:842 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x8c0/0x1430 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb65/0x1e40 kernel/workqueue.c:3385
worker_thread+0xee4/0x1590 kernel/workqueue.c:3466
kthread+0x53f/0x600 kernel/kthread.c:436
ret_from_fork+0x20f/0x8d0 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:4576 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_node_track_caller_noprof+0x4f6/0x1750 mm/slub.c:5403
kmalloc_reserve net/core/skbuff.c:635 [inline]
__alloc_skb+0x90d/0x1190 net/core/skbuff.c:713
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x3f2/0x1430 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb65/0x1e40 kernel/workqueue.c:3385
worker_thread+0xee4/0x1590 kernel/workqueue.c:3466
kthread+0x53f/0x600 kernel/kthread.c:436
ret_from_fork+0x20f/0x8d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

CPU: 0 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
=====================================================

Tested on:

commit: 59bd5ae0 Merge tag 'for-v7.1' of git://git.kernel.org/..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=15ba6f16580000
kernel config: https://syzkaller.appspot.com/x/.config?x=dd34a4e3f8a96df8
dashboard link: https://syzkaller.appspot.com/bug?extid=217eb327242d08197efb
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=10e24702580000