Message-ID: <6859ea24.a00a0220.2e5631.0044.GAE@google.com>
Date: Mon, 23 Jun 2025 16:58:28 -0700
From: syzbot <syzbot+daba72c4af9915e9c894@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org, 
	mathieu.desnoyers@...icios.com, mhiramat@...nel.org, rostedt@...dmis.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [trace?] KASAN: slab-use-after-free Read in __free_filter

Hello,

syzbot found the following issue on:

HEAD commit:    86731a2a651e Linux 6.16-rc3
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1611eb0c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4ad206eb0100c6a2
dashboard link: https://syzkaller.appspot.com/bug?extid=daba72c4af9915e9c894
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=13b16dd4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17c7bb0c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a4314982a0cf/disk-86731a2a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8acf9467ceed/vmlinux-86731a2a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dddd9a796b01/bzImage-86731a2a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+daba72c4af9915e9c894@...kaller.appspotmail.com

R10: 0000000000000001 R11: 0000000000000246 R12: 00007f0e9949d618
R13: 00007ffeb32f2178 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
==================================================================
BUG: KASAN: slab-use-after-free in free_prog kernel/trace/trace_events_filter.c:1288 [inline]
BUG: KASAN: slab-use-after-free in __free_filter.part.0+0x153/0x160 kernel/trace/trace_events_filter.c:1312
Read of size 8 at addr ffff88801d78a9a0 by task syz-executor377/5826

CPU: 0 UID: 0 PID: 5826 Comm: syz-executor377 Not tainted 6.16.0-rc3-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 free_prog kernel/trace/trace_events_filter.c:1288 [inline]
 __free_filter.part.0+0x153/0x160 kernel/trace/trace_events_filter.c:1312
 __free_filter kernel/trace/trace_events_filter.c:1309 [inline]
 filter_free_subsystem_filters kernel/trace/trace_events_filter.c:1470 [inline]
 apply_subsystem_event_filter+0x1487/0x17a0 kernel/trace/trace_events_filter.c:2512
 subsystem_filter_write+0x95/0x120 kernel/trace/trace_events.c:2304
 vfs_write+0x2a0/0x1150 fs/read_write.c:684
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0e994323a9
Code: 48 83 c4 28 c3 e8 17 1a 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeb32f1f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffeb32f1fa0 RCX: 00007f0e994323a9
RDX: 0000000000000009 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: 00007ffeb32f1d37 R09: 00007f0e994a0037
R10: 0000000000000001 R11: 0000000000000246 R12: 00007f0e9949d618
R13: 00007ffeb32f2178 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Allocated by task 13:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 create_new_subsystem kernel/trace/trace_events.c:2742 [inline]
 event_subsystem_dir kernel/trace/trace_events.c:2815 [inline]
 event_create_dir+0x906/0xd40 kernel/trace/trace_events.c:3037
 __trace_early_add_event_dirs+0xae/0x210 kernel/trace/trace_events.c:4199
 early_event_add_tracer kernel/trace/trace_events.c:4386 [inline]
 event_trace_init+0x144/0x1f0 kernel/trace/trace_events.c:4540
 tracer_init_tracefs_work_func+0x12/0x3d0 kernel/trace/trace.c:10480
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5826:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 __free_filter kernel/trace/trace_events_filter.c:1309 [inline]
 free_filter_list+0xa5/0x240 kernel/trace/trace_events_filter.c:1357
 filter_free_subsystem_filters kernel/trace/trace_events_filter.c:1463 [inline]
 apply_subsystem_event_filter+0x12be/0x17a0 kernel/trace/trace_events_filter.c:2512
 subsystem_filter_write+0x95/0x120 kernel/trace/trace_events.c:2304
 vfs_write+0x2a0/0x1150 fs/read_write.c:684
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88801d78a9a0
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 freed 16-byte region [ffff88801d78a9a0, ffff88801d78a9b0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d78a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b841640 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 4520983069, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4347
 kvasprintf+0xbc/0x160 lib/kasprintf.c:25
 kvasprintf_const+0x66/0x1a0 lib/kasprintf.c:49
 kobject_set_name_vargs+0x5a/0x140 lib/kobject.c:274
 dev_set_name+0xc7/0x100 drivers/base/core.c:3495
 device_add+0xe59/0x1a70 drivers/base/core.c:3607
 tick_init_sysfs kernel/time/clockevents.c:758 [inline]
 clockevents_init_sysfs+0x157/0x2d0 kernel/time/clockevents.c:774
 do_one_initcall+0x120/0x6e0 init/main.c:1274
 do_initcall_level init/main.c:1336 [inline]
 do_initcalls init/main.c:1352 [inline]
 do_basic_setup init/main.c:1371 [inline]
 kernel_init_freeable+0x5c2/0x900 init/main.c:1584
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88801d78a880: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
 ffff88801d78a900: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
>ffff88801d78a980: 00 00 fc fc fa fb fc fc 00 00 fc fc 00 00 fc fc
                               ^
 ffff88801d78aa00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
 ffff88801d78aa80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
==================================================================


---
This report is generated by a bot. It may contain errors.
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