[syzbot] [pvrusb2?] [usb?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot] [pvrusb2?] [usb?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    24be4d0b46bb arch/arm64/mm/fault: Fix undeclared variable ..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=11383b04a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f9122dc1c4589f4c
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14e2e43ca80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=109a3a90a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b64cbb1118f1/disk-24be4d0b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/568048c1dd0d/vmlinux-24be4d0b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84ac264152e7/bzImage-24be4d0b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff88810eb986d8 by task kworker/0:0/7

CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.4.0-syzkaller-11311-g24be4d0b46bb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: usb_hub_wq hub_event

Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:364
 print_report mm/kasan/report.c:475 [inline]
 kasan_report+0x11d/0x130 mm/kasan/report.c:588
 pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
 pvr_disconnect+0x80/0xf0 drivers/media/usb/pvrusb2/pvrusb2-main.c:79
 usb_unbind_interface+0x1dc/0x8e0 drivers/usb/core/driver.c:458
 device_remove drivers/base/dd.c:569 [inline]
 device_remove+0x11f/0x170 drivers/base/dd.c:561
 __device_release_driver drivers/base/dd.c:1270 [inline]
 device_release_driver_internal+0x443/0x610 drivers/base/dd.c:1293
 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
 device_del+0x399/0xa30 drivers/base/core.c:3814
 usb_disable_device+0x360/0x7b0 drivers/usb/core/message.c:1420
 usb_disconnect+0x2db/0x8a0 drivers/usb/core/hub.c:2253
 hub_port_connect drivers/usb/core/hub.c:5261 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5566 [inline]
 port_event drivers/usb/core/hub.c:5726 [inline]
 hub_event+0x2073/0x4ed0 drivers/usb/core/hub.c:5808
 process_one_work+0xa34/0x16f0 kernel/workqueue.c:2597
 process_scheduled_works kernel/workqueue.c:2664 [inline]
 worker_thread+0x881/0x10c0 kernel/workqueue.c:2750
 kthread+0x344/0x440 kernel/kthread.c:389
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Allocated by task 7:
 kasan_save_stack+0x22/0x40 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+0x7b/0x90 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:579 [inline]
 kzalloc include/linux/slab.h:700 [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+0x30f/0x960 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x240/0xca0 drivers/base/dd.c:658
 __driver_probe_device+0x1df/0x4b0 drivers/base/dd.c:798
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:828
 __device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:956
 bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
 __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1028
 bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
 device_add+0x112d/0x1a40 drivers/base/core.c:3625
 usb_set_configuration+0x1196/0x1bc0 drivers/usb/core/message.c:2211
 usb_generic_driver_probe+0xcf/0x130 drivers/usb/core/generic.c:238
 usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x240/0xca0 drivers/base/dd.c:658
 __driver_probe_device+0x1df/0x4b0 drivers/base/dd.c:798
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:828
 __device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:956
 bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
 __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1028
 bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
 device_add+0x112d/0x1a40 drivers/base/core.c:3625
 usb_new_device+0xcb2/0x19d0 drivers/usb/core/hub.c:2590
 hub_port_connect drivers/usb/core/hub.c:5422 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5566 [inline]
 port_event drivers/usb/core/hub.c:5726 [inline]
 hub_event+0x2e3d/0x4ed0 drivers/usb/core/hub.c:5808
 process_one_work+0xa34/0x16f0 kernel/workqueue.c:2597
 process_scheduled_works kernel/workqueue.c:2664 [inline]
 worker_thread+0x881/0x10c0 kernel/workqueue.c:2750
 kthread+0x344/0x440 kernel/kthread.c:389
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Freed by task 892:
 kasan_save_stack+0x22/0x40 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:521
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x144/0x1b0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:162 [inline]
 slab_free_hook mm/slub.c:1792 [inline]
 slab_free_freelist_hook mm/slub.c:1818 [inline]
 slab_free mm/slub.c:3801 [inline]
 __kmem_cache_free+0xa1/0x350 mm/slub.c:3814
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
 pvr2_context_thread_func+0x664/0x8e0 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x344/0x440 kernel/kthread.c:389
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

The buggy address belongs to the object at ffff88810eb98600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 216 bytes inside of
 freed 256-byte region [ffff88810eb98600, ffff88810eb98700)

The buggy address belongs to the physical page:
page:ffffea00043ae600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10eb98
head:ffffea00043ae600 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x200000000010200(slab|head|node=0|zone=2)
page_type: 0xffffffff()
raw: 0200000000010200 ffff888100041b40 ffffea00043ae300 0000000000000003
raw: 0000000000000000 0000000000100010 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 7338785555, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1570
 prep_new_page mm/page_alloc.c:1577 [inline]
 get_page_from_freelist+0x13d5/0x2cb0 mm/page_alloc.c:3221
 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4477
 alloc_page_interleave+0x1e/0x1e0 mm/mempolicy.c:2112
 alloc_pages+0x233/0x270 mm/mempolicy.c:2274
 alloc_slab_page mm/slub.c:1862 [inline]
 allocate_slab+0x25f/0x390 mm/slub.c:2009
 new_slab mm/slub.c:2062 [inline]
 ___slab_alloc+0xbc3/0x15d0 mm/slub.c:3215
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3314
 __slab_alloc_node mm/slub.c:3367 [inline]
 slab_alloc_node mm/slub.c:3460 [inline]
 __kmem_cache_alloc_node+0x2c3/0x300 mm/slub.c:3509
 __do_kmalloc_node mm/slab_common.c:984 [inline]
 __kmalloc_node_track_caller+0x4f/0x1a0 mm/slab_common.c:1005
 __do_krealloc mm/slab_common.c:1373 [inline]
 krealloc+0x5e/0xf0 mm/slab_common.c:1406
 add_sysfs_param+0xca/0x960 kernel/params.c:652
 kernel_add_sysfs_param kernel/params.c:813 [inline]
 param_sysfs_builtin kernel/params.c:852 [inline]
 param_sysfs_builtin_init+0x241/0x440 kernel/params.c:986
 do_one_initcall+0x105/0x630 init/main.c:1232
 do_initcall_level init/main.c:1294 [inline]
 do_initcalls init/main.c:1310 [inline]
 do_basic_setup init/main.c:1329 [inline]
 kernel_init_freeable+0x649/0xb90 init/main.c:1546
 kernel_init+0x1e/0x2c0 init/main.c:1437
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810eb98580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810eb98600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810eb98680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88810eb98700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810eb98780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
This report is generated by a bot. It may contain errors.
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syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

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#syz undup

Re: [syzbot] [pvrusb2?] [usb?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[Ricardo B. Marliere]

[-- Attachment #1: Type: text/plain, Size: 115 bytes --]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git ce9ecca0238b140b88f43859b211c9fdfd8e5b70

[-- Attachment #2: patch --]
[-- Type: text/x-patch, Size: 970 bytes --]

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c
index 14170a5d72b3..e3356f94e50e 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-context.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c
@@ -27,9 +27,16 @@ static int pvr2_context_cleaned_flag;
 static struct task_struct *pvr2_context_thread_ptr;
 
 
+static int pvr2_context_shutok(void)
+{
+	return pvr2_context_cleanup_flag && (pvr2_context_exist_first == NULL);
+}
+
+
 static void pvr2_context_set_notify(struct pvr2_context *mp, int fl)
 {
 	int signal_flag = 0;
+	if (pvr2_context_shutok()) return;
 	mutex_lock(&pvr2_context_mutex);
 	if (fl) {
 		if (!mp->notify_flag) {
@@ -140,12 +147,6 @@ static void pvr2_context_check(struct pvr2_context *mp)
 }
 
 
-static int pvr2_context_shutok(void)
-{
-	return pvr2_context_cleanup_flag && (pvr2_context_exist_first == NULL);
-}
-
-
 static int pvr2_context_thread_func(void *foo)
 {
 	struct pvr2_context *mp;

Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot]

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: Important functionality might not be entirely working.
pvrusb2: Please consider contacting the driver author to help with further stabilization of the driver.
pvrusb2: **********
usb 1-1: USB disconnect, device number 102
pvrusb2: Device being rendered inoperable
==================================================================
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2fa/0x350 drivers/media/usb/pvrusb2/pvrusb2-context.c:42
Read of size 4 at addr ffff8881093becd8 by task kworker/0:0/8

CPU: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.6.0-rc2-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: usb_hub_wq hub_event
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
 pvr2_context_set_notify+0x2fa/0x350 drivers/media/usb/pvrusb2/pvrusb2-context.c:42
 pvr_disconnect+0x80/0xf0 drivers/media/usb/pvrusb2/pvrusb2-main.c:79
 usb_unbind_interface+0x1dd/0x8d0 drivers/usb/core/driver.c:458
 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:3813
 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416
 usb_disconnect+0x2e1/0x890 drivers/usb/core/hub.c:2252
 hub_port_connect drivers/usb/core/hub.c:5280 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
 port_event drivers/usb/core/hub.c:5740 [inline]
 hub_event+0x1be0/0x4f30 drivers/usb/core/hub.c:5822
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 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 8:
 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+0x87/0x90 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 pvr2_context_create+0x53/0x2a0 drivers/media/usb/pvrusb2/pvrusb2-context.c:208
 pvr_probe+0x25/0xe0 drivers/media/usb/pvrusb2/pvrusb2-main.c:54
 usb_probe_interface+0x307/0x930 drivers/usb/core/driver.c:396
 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:3624
 usb_set_configuration+0x10cb/0x1c40 drivers/usb/core/message.c:2207
 usb_generic_driver_probe+0xca/0x130 drivers/usb/core/generic.c:238
 usb_probe_device+0xda/0x2c0 drivers/usb/core/driver.c:293
 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:3624
 usb_new_device+0xd80/0x1960 drivers/usb/core/hub.c:2589
 hub_port_connect drivers/usb/core/hub.c:5440 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
 port_event drivers/usb/core/hub.c:5740 [inline]
 hub_event+0x2e62/0x4f30 drivers/usb/core/hub.c:5822
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 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

Freed by task 901:
 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+0x13c/0x190 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 mm/slub.c:1826 [inline]
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xff/0x330 mm/slub.c:3822
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:144 [inline]
 pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:159
 kthread+0x33c/0x440 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

The buggy address belongs to the object at ffff8881093bec00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 216 bytes inside of
 freed 256-byte region [ffff8881093bec00, ffff8881093bed00)

The buggy address belongs to the physical page:
page:ffffea000424ef80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1093be
head:ffffea000424ef80 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x200000000000840(slab|head|node=0|zone=2)
page_type: 0xffffffff()
raw: 0200000000000840 ffff888100041b40 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8817323426, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10e1/0x2fd0 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 alloc_page_interleave+0x1e/0x230 mm/mempolicy.c:2131
 alloc_pages+0x22a/0x270 mm/mempolicy.c:2293
 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+0x8c7/0x1580 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+0x12c/0x310 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]
 bus_add_driver+0x92/0x630 drivers/base/bus.c:657
 driver_register+0x15c/0x4a0 drivers/base/driver.c:246
 usb_register_driver+0x24f/0x500 drivers/usb/core/driver.c:1062
 do_one_initcall+0x117/0x630 init/main.c:1232
 do_initcall_level init/main.c:1294 [inline]
 do_initcalls init/main.c:1310 [inline]
 do_basic_setup init/main.c:1329 [inline]
 kernel_init_freeable+0x5bd/0x8f0 init/main.c:1547
 kernel_init+0x1c/0x2a0 init/main.c:1437
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881093beb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881093bec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881093bec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8881093bed00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881093bed80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         ce9ecca0 Linux 6.6-rc2
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13f01d0a680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59eae8406319284a
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
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=12ca2656680000

Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com

Tested on:

commit:         633b47cb Merge tag 'scsi-fixes' of git://git.kernel.or..
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=103d5e12680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=acc0013b40e239a2
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
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=14381d0a680000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[Ricardo B. Marliere]

Good one, but make sure to test against Greg usb-testing tree!

Thanks,
-	Ricardo

Re: [syzbot] [pvrusb2?] [usb?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[Ricardo B. Marliere]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 1053c4a4b8fcbd28386e80347e7c82d4d617e352

Re: [syzbot] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot]

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: Important functionality might not be entirely working.
pvrusb2: Please consider contacting the driver author to help with further stabilization of the driver.
pvrusb2: **********
usb 1-1: USB disconnect, device number 3
pvrusb2: Device being rendered inoperable
==================================================================
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff88812c3e68d8 by task kworker/0:2/699

CPU: 0 PID: 699 Comm: kworker/0:2 Not tainted 6.6.0-rc4-syzkaller-00064-g1053c4a4b8fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: usb_hub_wq hub_event
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
 pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
 pvr_disconnect+0x80/0xf0 drivers/media/usb/pvrusb2/pvrusb2-main.c:79
 usb_unbind_interface+0x1dd/0x8d0 drivers/usb/core/driver.c:458
 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:3813
 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416
 usb_disconnect+0x2e1/0x890 drivers/usb/core/hub.c:2252
 hub_port_connect drivers/usb/core/hub.c:5280 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
 port_event drivers/usb/core/hub.c:5740 [inline]
 hub_event+0x1be0/0x4f30 drivers/usb/core/hub.c:5822
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 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 699:
 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+0x87/0x90 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [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:396
 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:3624
 usb_set_configuration+0x10cb/0x1c40 drivers/usb/core/message.c:2207
 usb_generic_driver_probe+0xca/0x130 drivers/usb/core/generic.c:238
 usb_probe_device+0xda/0x2c0 drivers/usb/core/driver.c:293
 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:3624
 usb_new_device+0xd80/0x1960 drivers/usb/core/hub.c:2589
 hub_port_connect drivers/usb/core/hub.c:5440 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5580 [inline]
 port_event drivers/usb/core/hub.c:5740 [inline]
 hub_event+0x2e62/0x4f30 drivers/usb/core/hub.c:5822
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 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

Freed by task 902:
 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+0x13c/0x190 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 mm/slub.c:1826 [inline]
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xff/0x330 mm/slub.c:3822
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
 pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x33c/0x440 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

The buggy address belongs to the object at ffff88812c3e6800
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 216 bytes inside of
 freed 256-byte region [ffff88812c3e6800, ffff88812c3e6900)

The buggy address belongs to the physical page:
page:ffffea0004b0f980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c3e6
head:ffffea0004b0f980 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 ffffea0004722a80 dead000000000004
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 699, tgid 699 (kworker/0:2), ts 149486728006, free_ts 149464487231
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10e1/0x2fd0 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2297
 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+0x8c7/0x1580 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+0x12c/0x310 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]
 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:396
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x460/0xa20 mm/page_alloc.c:2312
 free_unref_page+0x33/0x2c0 mm/page_alloc.c:2405
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x4a/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 __kmem_cache_alloc_node+0x190/0x310 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1022 [inline]
 __kmalloc+0x4f/0x100 mm/slab_common.c:1036
 kmalloc include/linux/slab.h:603 [inline]
 tomoyo_realpath_from_path+0xb9/0x710 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x241/0x580 security/tomoyo/file.c:723
 security_file_ioctl+0x72/0xb0 security/security.c:2647
 __do_sys_ioctl fs/ioctl.c:865 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0xbb/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

Memory state around the buggy address:
 ffff88812c3e6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812c3e6800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88812c3e6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88812c3e6900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812c3e6980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         1053c4a4 Revert "usb: gadget: uvc: stop pump thread on..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1472423a680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a5e01246f94ceed9
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Re: [syzbot] [pvrusb2?] [usb?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[Ricardo B. Marliere]

[-- Attachment #1: Type: text/plain, Size: 115 bytes --]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git ce9ecca0238b140b88f43859b211c9fdfd8e5b70

[-- Attachment #2: 0001-media-pvrusb2-fix-use-after-free-on-context-disconne.patch --]
[-- Type: text/x-diff, Size: 1485 bytes --]

From cf7c3b08f80c4cdb7dd08cb977f29d41efebcf79 Mon Sep 17 00:00:00 2001
From: "Ricardo B. Marliere" <ricardo@marliere.net>
Date: Thu, 12 Oct 2023 18:26:47 -0300
Subject: [PATCH] media: pvrusb2: fix use after free on context disconnection

Upon module load, a kthread is created targeting the
pvr2_context_thread_func function, which may call pvr2_context_destroy
and thus call kfree() on the context object. However, that might happen
before the usb hub_event handler is able to notify the driver. This
patch adds a sanity check before the invalid read reported by syzbot,
within the context disconnection call stack.

Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
Reported-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000a02a4205fff8eb92@google.com/
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
 drivers/media/usb/pvrusb2/pvrusb2-context.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c
index 14170a5d72b3..1764674de98b 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-context.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c
@@ -268,7 +268,8 @@ void pvr2_context_disconnect(struct pvr2_context *mp)
 {
 	pvr2_hdw_disconnect(mp->hdw);
 	mp->disconnect_flag = !0;
-	pvr2_context_notify(mp);
+	if (!pvr2_context_shutok())
+		pvr2_context_notify(mp);
 }
 
 
-- 
2.42.0

Re: [syzbot] [usb?] [pvrusb2?] KASAN: slab-use-after-free Read in pvr2_context_set_notify

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com

Tested on:

commit:         ce9ecca0 Linux 6.6-rc2
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10be5209680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59eae8406319284a
dashboard link: https://syzkaller.appspot.com/bug?extid=621409285c4156a009b3
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=131dd84d680000

Note: testing is done by a robot and is best-effort only.