Re: [syzbot] [acpi?] KASAN: slab-use-after-free Read in software_node_notify_remove

syzbot
2025-04-06T14:09:05Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in set_secondary_fwnode

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f0934da5fa0 R15: 00007ffe7c9dc778
</TASK>
iommufd_mock iommufd_mock0: Adding to iommu group 0
==================================================================
BUG: KASAN: slab-use-after-free in fwnode_is_primary drivers/base/core.c:5105 [inline]
BUG: KASAN: slab-use-after-free in set_secondary_fwnode+0x89/0xd0 drivers/base/core.c:5167
Read of size 8 at addr ffff8880358f0440 by task syz.0.19/6201

CPU: 0 UID: 0 PID: 6201 Comm: syz.0.19 Not tainted 6.14.0-syzkaller-13525-g22ea69445c54 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0x16e/0x5b0 mm/kasan/report.c:521
kasan_report+0x143/0x180 mm/kasan/report.c:634
fwnode_is_primary drivers/base/core.c:5105 [inline]
set_secondary_fwnode+0x89/0xd0 drivers/base/core.c:5167
software_node_notify_remove+0x1a8/0x1e0 drivers/base/swnode.c:1112
device_platform_notify_remove drivers/base/core.c:2387 [inline]
device_del+0x594/0x9b0 drivers/base/core.c:3858
device_unregister+0x20/0xc0 drivers/base/core.c:3896
mock_dev_destroy drivers/iommu/iommufd/selftest.c:960 [inline]
iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1022 [inline]
iommufd_test+0x3715/0x56a0 drivers/iommu/iommufd/selftest.c:1866
iommufd_fops_ioctl+0x4fc/0x610 drivers/iommu/iommufd/main.c:419
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0934b8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0935a12038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0934da5fa0 RCX: 00007f0934b8d169
RDX: 0000200000000200 RSI: 0000000000003ba0 RDI: 0000000000000003
RBP: 00007f0935a12090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f0934da5fa0 R15: 00007ffe7c9dc778
</TASK>

Allocated by task 6201:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x9d/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__kmalloc_cache_noprof+0x236/0x370 mm/slub.c:4362
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
swnode_register+0x5a/0x540 drivers/base/swnode.c:790
fwnode_create_software_node+0x199/0x1f0 drivers/base/swnode.c:949
device_create_managed_software_node+0xd5/0x1f0 drivers/base/swnode.c:1060
mock_dev_create drivers/iommu/iommufd/selftest.c:942 [inline]
iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:989 [inline]
iommufd_test+0x3335/0x56a0 drivers/iommu/iommufd/selftest.c:1866
iommufd_fops_ioctl+0x4fc/0x610 drivers/iommu/iommufd/main.c:419
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6201:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2389 [inline]
slab_free mm/slub.c:4646 [inline]
kfree+0x198/0x430 mm/slub.c:4845
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x22f/0x480 lib/kobject.c:737
software_node_notify_remove+0x18d/0x1e0 drivers/base/swnode.c:1109
device_platform_notify_remove drivers/base/core.c:2387 [inline]
device_del+0x594/0x9b0 drivers/base/core.c:3858
device_unregister+0x20/0xc0 drivers/base/core.c:3896
mock_dev_destroy drivers/iommu/iommufd/selftest.c:960 [inline]
iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1022 [inline]
iommufd_test+0x3715/0x56a0 drivers/iommu/iommufd/selftest.c:1866
iommufd_fops_ioctl+0x4fc/0x610 drivers/iommu/iommufd/main.c:419
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880358f0400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
freed 512-byte region [ffff8880358f0400, ffff8880358f0600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x358f0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b041c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b041c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d63c01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5211, tgid 5211 (udevd), ts 44437391568, free_ts 41364354329
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1717
prep_new_page mm/page_alloc.c:1725 [inline]
get_page_from_freelist+0x352b/0x36c0 mm/page_alloc.c:3652
__alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4934
alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301
alloc_slab_page mm/slub.c:2459 [inline]
allocate_slab+0x8f/0x3a0 mm/slub.c:2623
new_slab mm/slub.c:2676 [inline]
___slab_alloc+0xc3b/0x1500 mm/slub.c:3862
__slab_alloc+0x58/0xa0 mm/slub.c:3952
__slab_alloc_node mm/slub.c:4027 [inline]
slab_alloc_node mm/slub.c:4188 [inline]
__kmalloc_cache_noprof+0x26a/0x370 mm/slub.c:4357
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
kernfs_fop_open+0x3a3/0xdf0 fs/kernfs/file.c:623
do_dentry_open+0xdec/0x1960 fs/open.c:956
vfs_open+0x3b/0x370 fs/open.c:1086
do_open fs/namei.c:3845 [inline]
path_openat+0x2caf/0x35d0 fs/namei.c:4004
do_filp_open+0x284/0x4e0 fs/namei.c:4031
do_sys_openat2+0x12b/0x1d0 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_openat fs/open.c:1460 [inline]
__se_sys_openat fs/open.c:1455 [inline]
__x64_sys_openat+0x249/0x2a0 fs/open.c:1455
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
page last free pid 5213 tgid 5213 stack trace:
create_dummy_stack mm/page_owner.c:94 [inline]
register_dummy_stack+0x8e/0xe0 mm/page_owner.c:100
init_page_owner+0x3e/0x790 mm/page_owner.c:118
invoke_init_callbacks mm/page_ext.c:148 [inline]
page_ext_init+0x731/0x790 mm/page_ext.c:497
mm_core_init+0x5b/0x70 mm/mm_init.c:2783

Memory state around the buggy address:
ffff8880358f0300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880358f0380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880358f0400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880358f0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880358f0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Tested on:

commit: 22ea6944 software node: Avoid use-after-free access in..
git tree: https://bitbucket.org/andy-shev/linux.git test-swnode
console output: https://syzkaller.appspot.com/x/log.txt?x=1276f404580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f2054704dd53fb80
dashboard link: https://syzkaller.appspot.com/bug?extid=2ff22910687ee0dfd48e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.