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From: syzbot <syzbot+ba5f49027aace342d24d@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	 tristmd@gmail.com
Subject: Re: [syzbot] [jfs?] KMSAN: uninit-value in BT_STACK_DUMP
Date: Fri, 17 Apr 2026 12:03:04 -0700	[thread overview]
Message-ID: <69e283e8.a00a0220.1bd0ca.001b.GAE@google.com> (raw)
In-Reply-To: <177644280177.3785830.6199963330622576626@talencesecurity.com>

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
 smap_restore arch/x86/include/asm/smap.h:90 [inline]
 get_shadow_origin_ptr mm/kmsan/instrumentation.c:39 [inline]
 __msan_metadata_ptr_for_load_4+0x2c/0x40 mm/kmsan/instrumentation.c:93
 do_csum lib/checksum.c:64 [inline]
 ip_fast_csum+0x1e6/0x3f0 lib/checksum.c:99
 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+0x8c0/0x1440 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb6c/0x1e60 kernel/workqueue.c:3385
 worker_thread+0xee4/0x15a0 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+0x4f6/0x1740 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+0x3f2/0x1440 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb6c/0x1e60 kernel/workqueue.c:3385
 worker_thread+0xee4/0x15a0 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: 34 Comm: kworker/u8:2 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:         d662a710 Merge tag 'dmaengine-7.1-rc1' of git://git.ke..
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=127aa4ce580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3dd68bb0183fc39c
dashboard link: https://syzkaller.appspot.com/bug?extid=ba5f49027aace342d24d
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=17ea1906580000


       reply	other threads:[~2026-04-17 19:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <177644280177.3785830.6199963330622576626@talencesecurity.com>
2026-04-17 19:03 ` syzbot [this message]
     [not found] <20260417101200.2489522-1-tristmd@gmail.com>
2026-04-17 11:43 ` [syzbot] [jfs?] KMSAN: uninit-value in BT_STACK_DUMP syzbot
     [not found] <CABPJ0vhxvUrsFsL7-q5UJeUOsy=gz4nUVJxCOLjBaPP5cB2hYA@mail.gmail.com>
2025-09-23 20:59 ` syzbot
     [not found] <20250506142010.802613-1-richard120310@gmail.com>
2025-05-06 15:38 ` syzbot
     [not found] <20250506130020.798216-1-richard120310@gmail.com>
2025-05-06 13:31 ` syzbot
2025-05-06  3:08 syzbot

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