linux-kernel - Re: [syzbot] [iommu?] KMSAN: uninit-value in pfn_reader

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <69749dff.a00a0220.33ccc7.0004.GAE@google.com>
Date: Sat, 24 Jan 2026 02:25:03 -0800
From: syzbot <syzbot+df28076a30d726933015@...kaller.appspotmail.com>
To: kartikey406@...il.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [iommu?] KMSAN: uninit-value in pfn_reader_next

Hello,

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

=====================================================
BUG: KMSAN: uninit-value in batch_add_pfn_num drivers/iommu/iommufd/pages.c:365 [inline]
BUG: KMSAN: uninit-value in batch_add_pfn drivers/iommu/iommufd/pages.c:398 [inline]
BUG: KMSAN: uninit-value in batch_from_domain+0xe8c/0x1010 drivers/iommu/iommufd/pages.c:425
 batch_add_pfn_num drivers/iommu/iommufd/pages.c:365 [inline]
 batch_add_pfn drivers/iommu/iommufd/pages.c:398 [inline]
 batch_from_domain+0xe8c/0x1010 drivers/iommu/iommufd/pages.c:425
 iopt_area_unpin_domain drivers/iommu/iommufd/pages.c:1687 [inline]
 __iopt_area_unfill_domain+0xccf/0x1b90 drivers/iommu/iommufd/pages.c:1773
 iopt_area_unfill_domain+0x100/0x140 drivers/iommu/iommufd/pages.c:1828
 iopt_unfill_domain drivers/iommu/iommufd/io_pagetable.c:1025 [inline]
 iopt_table_remove_domain+0xada/0x1010 drivers/iommu/iommufd/io_pagetable.c:1269
 iommufd_hwpt_paging_destroy+0x21e/0x540 drivers/iommu/iommufd/hw_pagetable.c:30
 iommufd_object_remove+0x4c8/0x6c0 drivers/iommu/iommufd/main.c:273
 iommufd_object_put_and_try_destroy drivers/iommu/iommufd/iommufd_private.h:268 [inline]
 iommufd_hw_pagetable_put drivers/iommu/iommufd/iommufd_private.h:461 [inline]
 iommufd_hw_pagetable_detach+0x6e3/0xa10 drivers/iommu/iommufd/device.c:714
 iommufd_device_detach+0x38/0xe0 drivers/iommu/iommufd/device.c:1059
 iommufd_selftest_destroy+0x9e/0x100 drivers/iommu/iommufd/selftest.c:1951
 iommufd_fops_release+0x1e0/0x5f0 drivers/iommu/iommufd/main.c:361
 __fput+0x60e/0x1050 fs/file_table.c:468
 ____fput+0x25/0x30 fs/file_table.c:496
 task_work_run+0x208/0x2b0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0x2ff/0x1b20 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x1d7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable batch created at:
 __iopt_area_unfill_domain+0xa8/0x1b90 drivers/iommu/iommufd/pages.c:1738
 iopt_area_unfill_domain+0x100/0x140 drivers/iommu/iommufd/pages.c:1828

CPU: 0 UID: 0 PID: 6581 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
=====================================================


Tested on:

commit:         62085877 Merge tag 'kbuild-fixes-6.19-2' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1642c452580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8bf02b9e495b9fcd
dashboard link: https://syzkaller.appspot.com/bug?extid=df28076a30d726933015
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=158cc452580000