Message-ID: <0000000000001bfca206042a8bbc@google.com>
Date:   Wed, 30 Aug 2023 14:23:49 -0700
From:   syzbot <syzbot+60db9f652c92d5bacba4@...kaller.appspotmail.com>
To:     bp@...en8.de, brauner@...nel.org, dave.hansen@...ux.intel.com,
        hpa@...or.com, linux-kernel@...r.kernel.org, mingo@...hat.com,
        syzkaller-bugs@...glegroups.com, tglx@...utronix.de, x86@...nel.org
Subject: [syzbot] [kernel?] KASAN: slab-use-after-free Read in pwq_release_workfn

Hello,

syzbot found the following issue on:

HEAD commit:    626932085009 Add linux-next specific files for 20230825
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12268740680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8a8c992a790e5073
dashboard link: https://syzkaller.appspot.com/bug?extid=60db9f652c92d5bacba4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e25db7a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15b154c0680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46ec18b3c2fb/disk-62693208.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b4ea0cb78498/vmlinux-62693208.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5fb3938c7272/bzImage-62693208.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+60db9f652c92d5bacba4@...kaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in pwq_release_workfn+0x339/0x380 kernel/workqueue.c:4124
Read of size 4 at addr ffff888027b831c0 by task pool_workqueue_/3

CPU: 0 PID: 3 Comm: pool_workqueue_ Not tainted 6.5.0-rc7-next-20230825-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 pwq_release_workfn+0x339/0x380 kernel/workqueue.c:4124
 kthread_worker_fn+0x2fc/0xa80 kernel/kthread.c:823
 kthread+0x33a/0x430 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Allocated by task 5054:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 alloc_workqueue+0x16f/0x1490 kernel/workqueue.c:4684
 kvm_mmu_init_tdp_mmu+0x23/0x100 arch/x86/kvm/mmu/tdp_mmu.c:19
 kvm_mmu_init_vm+0x248/0x2e0 arch/x86/kvm/mmu/mmu.c:6180
 kvm_arch_init_vm+0x39/0x720 arch/x86/kvm/x86.c:12311
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1222 [inline]
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:5089 [inline]
 kvm_dev_ioctl+0xa31/0x1c20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:5131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5054:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1800 [inline]
 slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xb8/0x2f0 mm/slub.c:3822
 alloc_workqueue+0xe76/0x1490 kernel/workqueue.c:4746
 kvm_mmu_init_tdp_mmu+0x23/0x100 arch/x86/kvm/mmu/tdp_mmu.c:19
 kvm_mmu_init_vm+0x248/0x2e0 arch/x86/kvm/mmu/mmu.c:6180
 kvm_arch_init_vm+0x39/0x720 arch/x86/kvm/x86.c:12311
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1222 [inline]
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:5089 [inline]
 kvm_dev_ioctl+0xa31/0x1c20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:5131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888027b83000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 448 bytes inside of
 freed 512-byte region [ffff888027b83000, ffff888027b83200)

The buggy address belongs to the physical page:
page:ffffea00009ee000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27b80
head:ffffea00009ee000 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888012c41c80 ffffea000084fd00 dead000000000002
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
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 3260, tgid 3260 (kworker/u4:1), ts 17219877730, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1530
 prep_new_page mm/page_alloc.c:1537 [inline]
 get_page_from_freelist+0xf17/0x2e50 mm/page_alloc.c:3200
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4456
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298
 alloc_slab_page mm/slub.c:1870 [inline]
 allocate_slab+0x251/0x380 mm/slub.c:2017
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8be/0x1570 mm/slub.c:3223
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 __kmem_cache_alloc_node+0x137/0x350 mm/slub.c:3517
 kmalloc_trace+0x25/0xe0 mm/slab_common.c:1114
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 alloc_bprm+0x51/0xaf0 fs/exec.c:1514
 kernel_execve+0xaf/0x4e0 fs/exec.c:1989
 call_usermodehelper_exec_async+0x256/0x4c0 kernel/umh.c:110
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888027b83080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888027b83100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888027b83180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888027b83200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888027b83280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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