Message-ID: <67c099eb.050a0220.222324.026a.GAE@google.com>
Date: Thu, 27 Feb 2025 08:59:23 -0800
From: syzbot <syzbot+aef8e425f1a85ee5ef1c@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, luto@...nel.org, netdev@...r.kernel.org, 
	peterz@...radead.org, syzkaller-bugs@...glegroups.com, tglx@...utronix.de
Subject: [syzbot] [kernel?] KASAN: slab-use-after-free Read in task_work_run

Hello,

syzbot found the following issue on:

HEAD commit:    63817c771194 selftests/bpf: Test struct_ops program with _..
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13ccf498580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1
dashboard link: https://syzkaller.appspot.com/bug?extid=aef8e425f1a85ee5ef1c
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12d306e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b31ec77253e7/disk-63817c77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/07bea500bd9d/vmlinux-63817c77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7a0b65578ed5/bzImage-63817c77.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aef8e425f1a85ee5ef1c@...kaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in task_work_run+0x22b/0x310 kernel/task_work.c:226
Read of size 8 at addr ffff888028b97a18 by task syz.4.416/7301

CPU: 1 UID: 0 PID: 7301 Comm: syz.4.416 Not tainted 6.14.0-rc3-syzkaller-g63817c771194 #0
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
 task_work_run+0x22b/0x310 kernel/task_work.c:226
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f489a58d169
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:00007f489b4cf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffff2 RBX: 00007f489a7a5fa0 RCX: 00007f489a58d169
RDX: 000000110e22fff6 RSI: 00000000c004743e RDI: 0000000000000003
RBP: 00007f489a60e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f489a7a5fa0 R15: 00007ffe5af01388
 </TASK>

Allocated by task 7301:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4216
 perf_event_alloc+0x157/0x1e40 kernel/events/core.c:12240
 __do_sys_perf_event_open kernel/events/core.c:12875 [inline]
 __se_sys_perf_event_open+0xa5d/0x34b0 kernel/events/core.c:12765
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 24:
 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:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4711
 rcu_do_batch kernel/rcu/tree.c:2546 [inline]
 rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2802
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 run_ksoftirqd+0xca/0x130 kernel/softirq.c:950
 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548
 task_work_add+0xb8/0x450 kernel/task_work.c:65
 __perf_event_overflow+0x78d/0xdc0 kernel/events/core.c:9945
 perf_swevent_event+0x317/0x680
 do_perf_sw_event kernel/events/core.c:10185 [inline]
 ___perf_sw_event+0x4f3/0x730 kernel/events/core.c:10212
 __perf_sw_event+0xff/0x1b0 kernel/events/core.c:10224
 perf_sw_event include/linux/perf_event.h:1503 [inline]
 do_user_addr_fault arch/x86/mm/fault.c:1284 [inline]
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x710/0x8b0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

The buggy address belongs to the object at ffff888028b97590
 which belongs to the cache perf_event of size 1456
The buggy address is located 1160 bytes inside of
 freed 1456-byte region [ffff888028b97590, ffff888028b97b40)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28b90
head: order:3 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 ffff88801b091500 ffffea0001f63400 dead000000000002
raw: 0000000000000000 0000000080140014 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b091500 ffffea0001f63400 dead000000000002
head: 0000000000000000 0000000080140014 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000a2e401 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6118, tgid 6115 (syz.1.31), ts 147556510632, free_ts 147513456959
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_node_noprof+0x269/0x380 mm/slub.c:4216
 perf_event_alloc+0x157/0x1e40 kernel/events/core.c:12240
 __do_sys_perf_event_open kernel/events/core.c:12875 [inline]
 __se_sys_perf_event_open+0xa5d/0x34b0 kernel/events/core.c:12765
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5968 tgid 5968 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 discard_slab mm/slub.c:2684 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3153
 put_cpu_partial+0x17c/0x250 mm/slub.c:3228
 __slab_free+0x290/0x380 mm/slub.c:4479
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171
 getname_kernel+0x59/0x2f0 fs/namei.c:250
 kern_path+0x1d/0x50 fs/namei.c:2772
 do_loopback+0xc9/0x4f0 fs/namespace.c:2817
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888028b97900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028b97980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028b97a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888028b97a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028b97b00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


---
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