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Date: Thu, 15 Feb 2024 20:58:03 -0800
In-Reply-To: <20240216004250.1196-1-hdanton@sina.com>
Message-ID: <000000000000c43ecc06117896ab@google.com>
Subject: Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in
 pvr2_context_set_notify (2)
From: syzbot <syzbot+ce750e124675d4599449@syzkaller.appspotmail.com>
To: hdanton@sina.com, linux-kernel@vger.kernel.org, 
	syzkaller-bugs@googlegroups.com
Content-Type: text/plain; charset="UTF-8"

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in pvr2_context_set_notify

pvrusb2: You might need to power cycle the pvrusb2 device in order to recover.
==================================================================
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2ba/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:48
Read of size 4 at addr ffff88810fb02ed8 by task pvrusb2-context/902

CPU: 0 PID: 902 Comm: pvrusb2-context Not tainted 6.8.0-rc4-syzkaller-00180-g4f5e5092fdbf-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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:377 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:488
 kasan_report+0xda/0x110 mm/kasan/report.c:601
 pvr2_context_set_notify+0x2ba/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:48
 pvr2_context_thread_func+0x10d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:157
 kthread+0x2c6/0x3a0 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:242
 </TASK>

Allocated by task 724:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
 __kasan_kmalloc+0x87/0x90 mm/kasan/common.c:389
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 pvr2_context_create+0x53/0x2a0 drivers/media/usb/pvrusb2/pvrusb2-context.c:207
 pvr_probe+0x25/0xe0 drivers/media/usb/pvrusb2/pvrusb2-main.c:54
 usb_probe_interface+0x307/0x930 drivers/usb/core/driver.c:399
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x234/0xc90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
 __device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
 bus_for_each_drv+0x157/0x1d0 drivers/base/bus.c:457
 __device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
 bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
 device_add+0x117e/0x1aa0 drivers/base/core.c:3625
 usb_set_configuration+0x10cb/0x1c40 drivers/usb/core/message.c:2207
 usb_generic_driver_probe+0xad/0x110 drivers/usb/core/generic.c:254
 usb_probe_device+0xec/0x350 drivers/usb/core/driver.c:294
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x234/0xc90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
 __device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
 bus_for_each_drv+0x157/0x1d0 drivers/base/bus.c:457
 __device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
 bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
 device_add+0x117e/0x1aa0 drivers/base/core.c:3625
 usb_new_device+0xd90/0x1a10 drivers/usb/core/hub.c:2614
 hub_port_connect drivers/usb/core/hub.c:5483 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5623 [inline]
 port_event drivers/usb/core/hub.c:5783 [inline]
 hub_event+0x2e62/0x4f40 drivers/usb/core/hub.c:5865
 process_one_work+0x886/0x15d0 kernel/workqueue.c:2633
 process_scheduled_works kernel/workqueue.c:2706 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787
 kthread+0x2c6/0x3a0 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:242

Freed by task 724:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
 poison_slab_object mm/kasan/common.c:241 [inline]
 __kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kfree+0x105/0x340 mm/slub.c:4409
 pvr_disconnect+0x80/0xf0 drivers/media/usb/pvrusb2/pvrusb2-main.c:79
 usb_unbind_interface+0x1dd/0x8d0 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:569 [inline]
 device_remove+0x11f/0x170 drivers/base/dd.c:561
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1295
 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
 device_del+0x39a/0xa50 drivers/base/core.c:3814
 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416
 usb_disconnect+0x2e1/0x910 drivers/usb/core/hub.c:2267
 hub_port_connect drivers/usb/core/hub.c:5323 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5623 [inline]
 port_event drivers/usb/core/hub.c:5783 [inline]
 hub_event+0x1be0/0x4f40 drivers/usb/core/hub.c:5865
 process_one_work+0x886/0x15d0 kernel/workqueue.c:2633
 process_scheduled_works kernel/workqueue.c:2706 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787
 kthread+0x2c6/0x3a0 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:242

The buggy address belongs to the object at ffff88810fb02e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 216 bytes inside of
 freed 256-byte region [ffff88810fb02e00, ffff88810fb02f00)

The buggy address belongs to the physical page:
page:ffffea00043ec080 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10fb02
head:ffffea00043ec080 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x200000000000840(slab|head|node=0|zone=2)
page_type: 0xffffffff()
raw: 0200000000000840 ffff888100041b40 ffffea00041ef600 0000000000000002
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5358, tgid 5358 (kworker/1:4), ts 131458586273, free_ts 131438325014
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1533
 prep_new_page mm/page_alloc.c:1540 [inline]
 get_page_from_freelist+0x139c/0x3470 mm/page_alloc.c:3311
 __alloc_pages+0x228/0x2250 mm/page_alloc.c:4567
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2190 [inline]
 allocate_slab mm/slub.c:2354 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2407
 ___slab_alloc+0x4b0/0x1860 mm/slub.c:3540
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3625
 __slab_alloc_node mm/slub.c:3678 [inline]
 slab_alloc_node mm/slub.c:3850 [inline]
 kmalloc_trace+0x2ce/0x300 mm/slub.c:4007
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 pvr2_context_create+0x53/0x2a0 drivers/media/usb/pvrusb2/pvrusb2-context.c:207
 pvr_probe+0x25/0xe0 drivers/media/usb/pvrusb2/pvrusb2-main.c:54
 usb_probe_interface+0x307/0x930 drivers/usb/core/driver.c:399
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x234/0xc90 drivers/base/dd.c:658
 __driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830
 __device_attach_driver+0x1d4/0x300 drivers/base/dd.c:958
 bus_for_each_drv+0x157/0x1d0 drivers/base/bus.c:457
 __device_attach+0x1e8/0x4b0 drivers/base/dd.c:1030
page last free pid 5341 tgid 5341 stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1140 [inline]
 free_unref_page_prepare+0x504/0xae0 mm/page_alloc.c:2346
 free_unref_page+0x33/0x2d0 mm/page_alloc.c:2486
 qlink_free mm/kasan/quarantine.c:160 [inline]
 qlist_free_all+0x58/0x150 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x4a/0x70 mm/kasan/common.c:324
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc+0x131/0x2e0 mm/slub.c:3867
 getname_flags.part.0+0x50/0x4e0 fs/namei.c:140
 getname_flags+0x9c/0xf0 include/linux/audit.h:322
 vfs_fstatat+0x9a/0x140 fs/stat.c:303
 __do_sys_newfstatat+0x98/0x110 fs/stat.c:468
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffff88810fb02d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810fb02e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810fb02e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88810fb02f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810fb02f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         4f5e5092 Merge tag 'net-6.8-rc5' of git://git.kernel.o..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=17133c1c180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4f5e432f25b85a97
dashboard link: https://syzkaller.appspot.com/bug?extid=ce750e124675d4599449
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12c58494180000