[syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8096acd7442e Merge tag 'net-5.14-rc2' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167ca94a300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5294764a378649cb
dashboard link: https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
compiler:       Debian clang version 11.0.1-2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d68024300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16e4f180300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
BUG: KASAN: slab-out-of-bounds in do_raw_spin_lock+0x4f5/0x8e0 kernel/locking/spinlock_debug.c:112
Read of size 4 at addr ffff88802b46ce14 by task kworker/0:6/8471

CPU: 0 PID: 8471 Comm: kworker/0:6 Tainted: G        W         5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
 print_address_description+0x66/0x3b0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x163/0x210 mm/kasan/report.c:436
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x4f5/0x8e0 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:129 [inline]
 _raw_spin_lock_irq+0xba/0xf0 kernel/locking/spinlock.c:167
 do_wait_for_common+0x2e5/0x480 kernel/sched/completion.c:86
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 r871xu_dev_remove+0x83/0x460 drivers/staging/rtl8712/usb_intf.c:599
 usb_unbind_interface+0x1f2/0x860 drivers/usb/core/driver.c:458
 __device_release_driver drivers/base/dd.c:1201 [inline]
 device_release_driver_internal+0x51e/0x7b0 drivers/base/dd.c:1232
 bus_remove_device+0x2fd/0x410 drivers/base/bus.c:529
 device_del+0x6e1/0xc10 drivers/base/core.c:3540
 usb_disable_device+0x407/0x800 drivers/usb/core/message.c:1419
 usb_disconnect+0x33a/0x8a0 drivers/usb/core/hub.c:2221
 hub_port_connect+0x297/0x27a0 drivers/usb/core/hub.c:5151
 hub_port_connect_change+0x5d0/0xbf0 drivers/usb/core/hub.c:5440
 port_event+0xaee/0x1140 drivers/usb/core/hub.c:5586
 hub_event+0x48d/0xd80 drivers/usb/core/hub.c:5668
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Allocated by task 10:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x96/0xd0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slab.h:512 [inline]
 slab_alloc_node mm/slub.c:2981 [inline]
 kmem_cache_alloc_node+0x200/0x370 mm/slub.c:3017
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x52/0x980 kernel/fork.c:871
 copy_process+0x615/0x5b00 kernel/fork.c:1952
 kernel_clone+0x21a/0x7d0 kernel/fork.c:2509
 kernel_thread+0x146/0x1c0 kernel/fork.c:2561
 call_usermodehelper_exec_work+0x57/0x220 kernel/umh.c:174
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Last potentially related work creation:
 kasan_save_stack+0x27/0x50 mm/kasan/common.c:38
 kasan_record_aux_stack+0xee/0x120 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3029 [inline]
 call_rcu+0x1a0/0xa20 kernel/rcu/tree.c:3109
 schedule_tail+0xc/0xb0 kernel/sched/core.c:4619
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:280

The buggy address belongs to the object at ffff88802b46b880
 which belongs to the cache task_struct of size 6976
The buggy address is located 5524 bytes inside of
 6976-byte region [ffff88802b46b880, ffff88802b46d3c0)
The buggy address belongs to the page:
page:ffffea0000ad1a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b468
head:ffffea0000ad1a00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888140006280
raw: 0000000000000000 0000000000040004 00000001ffffffff 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 10, ts 43802781641, free_ts 43793596145
 prep_new_page mm/page_alloc.c:2433 [inline]
 get_page_from_freelist+0x779/0xa30 mm/page_alloc.c:4166
 __alloc_pages+0x26c/0x5f0 mm/page_alloc.c:5374
 alloc_slab_page mm/slub.c:1713 [inline]
 allocate_slab+0xf1/0x540 mm/slub.c:1853
 new_slab mm/slub.c:1916 [inline]
 new_slab_objects mm/slub.c:2662 [inline]
 ___slab_alloc+0x1cf/0x350 mm/slub.c:2825
 __slab_alloc mm/slub.c:2865 [inline]
 slab_alloc_node mm/slub.c:2947 [inline]
 kmem_cache_alloc_node+0x2ca/0x370 mm/slub.c:3017
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x52/0x980 kernel/fork.c:871
 copy_process+0x615/0x5b00 kernel/fork.c:1952
 kernel_clone+0x21a/0x7d0 kernel/fork.c:2509
 kernel_thread+0x146/0x1c0 kernel/fork.c:2561
 call_usermodehelper_exec_work+0x57/0x220 kernel/umh.c:174
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1343 [inline]
 free_pcp_prepare+0xc29/0xd20 mm/page_alloc.c:1394
 free_unref_page_prepare mm/page_alloc.c:3329 [inline]
 free_unref_page+0x7e/0x550 mm/page_alloc.c:3408
 kfree+0x287/0x2d0 mm/slub.c:4292
 request_firmware_work_func+0x175/0x250 drivers/base/firmware_loader/main.c:1081
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88802b46cd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802b46cd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88802b46ce00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                         ^
 ffff88802b46ce80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802b46cf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[Pavel Skripkin]

[-- Attachment #1: Type: text/plain, Size: 1624 bytes --]

On Mon, 19 Jul 2021 06:42:25 -0700
syzbot <syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    8096acd7442e Merge tag 'net-5.14-rc2' of
> git://git.kernel... git tree:       upstream
> console output:
> https://syzkaller.appspot.com/x/log.txt?x=167ca94a300000 kernel
> config:  https://syzkaller.appspot.com/x/.config?x=5294764a378649cb
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
> compiler:       Debian clang version 11.0.1-2 syz repro:
> https://syzkaller.appspot.com/x/repro.syz?x=14d68024300000 C
> reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16e4f180300000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit: Reported-by:
> syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in debug_spin_lock_before
> kernel/locking/spinlock_debug.c:83 [inline] BUG: KASAN:
> slab-out-of-bounds in do_raw_spin_lock+0x4f5/0x8e0
> kernel/locking/spinlock_debug.c:112 Read of size 4 at addr
> ffff88802b46ce14 by task kworker/0:6/8471
> 

I don't see any reason behind doing clean up stuff in firmware
callback. In my prevoius patch to this driver I fixed memory leak and, I
believed, that this approach won't trigger anything else... 

Let's just call device_release_driver() under parent lock in case of
firmware load failure and see if it works.

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


With regards,
Pavel Skripkin

[-- Attachment #2: 0001-staging-rtl8712-rewrite-error-handling.patch --]
[-- Type: text/x-patch, Size: 3966 bytes --]

From 754dff1a4e90cf0b41ab4dc3a06226738385476f Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Tue, 20 Jul 2021 14:05:02 +0300
Subject: [PATCH] staging: rtl8712: rewrite error handling

/* .... */

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/staging/rtl8712/hal_init.c | 30 ++++++++++++------
 drivers/staging/rtl8712/usb_intf.c | 50 +++++++++++++-----------------
 2 files changed, 42 insertions(+), 38 deletions(-)

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 22974277afa0..4eff3fdecdb8 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -29,21 +29,31 @@
 #define FWBUFF_ALIGN_SZ 512
 #define MAX_DUMP_FWSZ (48 * 1024)
 
+static void rtl871x_load_fw_fail(struct _adapter *adapter)
+{
+	struct usb_device *udev = adapter->dvobjpriv.pusbdev;
+	struct device *dev = &udev->dev;
+	struct device *parent = dev->parent;
+
+	complete(&adapter->rtl8712_fw_ready);
+
+	dev_err(&udev->dev, "r8712u: Firmware request failed\n");
+
+	if (parent)
+		device_lock(parent);
+
+	device_release_driver(dev);
+
+	if (parent)
+		device_unlock(parent);
+}
+
 static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
 {
 	struct _adapter *adapter = context;
 
 	if (!firmware) {
-		struct usb_device *udev = adapter->dvobjpriv.pusbdev;
-		struct usb_interface *usb_intf = adapter->pusb_intf;
-
-		dev_err(&udev->dev, "r8712u: Firmware request failed\n");
-		usb_put_dev(udev);
-		usb_set_intfdata(usb_intf, NULL);
-		r8712_free_drv_sw(adapter);
-		adapter->dvobj_deinit(adapter);
-		complete(&adapter->rtl8712_fw_ready);
-		free_netdev(adapter->pnetdev);
+		rtl871x_load_fw_fail(adapter);
 		return;
 	}
 	adapter->fw = firmware;
diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index 2434b13c8b12..6440febfd08d 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -591,35 +591,29 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
 {
 	struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
 	struct usb_device *udev = interface_to_usbdev(pusb_intf);
+	struct _adapter *padapter = netdev_priv(pnetdev);
+
+	/* never exit with a firmware callback pending */
+	wait_for_completion(&padapter->rtl8712_fw_ready);
+	usb_set_intfdata(pusb_intf, NULL);
+	release_firmware(padapter->fw);
+	if (drvpriv.drv_registered)
+		padapter->surprise_removed = true;
+	if (pnetdev->reg_state != NETREG_UNINITIALIZED)
+		unregister_netdev(pnetdev); /* will call netdev_close() */
+	flush_scheduled_work();
+	udelay(1);
+	/* Stop driver mlme relation timer */
+	r8712_stop_drv_timers(padapter);
+	r871x_dev_unload(padapter);
+	r8712_free_drv_sw(padapter);
+	free_netdev(pnetdev);
+
+	/* decrease the reference count of the usb device structure
+	 * when disconnect
+	 */
+	usb_put_dev(udev);
 
-	if (pnetdev) {
-		struct _adapter *padapter = netdev_priv(pnetdev);
-
-		/* never exit with a firmware callback pending */
-		wait_for_completion(&padapter->rtl8712_fw_ready);
-		pnetdev = usb_get_intfdata(pusb_intf);
-		usb_set_intfdata(pusb_intf, NULL);
-		if (!pnetdev)
-			goto firmware_load_fail;
-		release_firmware(padapter->fw);
-		if (drvpriv.drv_registered)
-			padapter->surprise_removed = true;
-		if (pnetdev->reg_state != NETREG_UNINITIALIZED)
-			unregister_netdev(pnetdev); /* will call netdev_close() */
-		flush_scheduled_work();
-		udelay(1);
-		/* Stop driver mlme relation timer */
-		r8712_stop_drv_timers(padapter);
-		r871x_dev_unload(padapter);
-		r8712_free_drv_sw(padapter);
-		free_netdev(pnetdev);
-
-		/* decrease the reference count of the usb device structure
-		 * when disconnect
-		 */
-		usb_put_dev(udev);
-	}
-firmware_load_fail:
 	/* If we didn't unplug usb dongle and remove/insert module, driver
 	 * fails on sitesurvey for the first time when device is up.
 	 * Reset usb port for sitesurvey fail issue.
-- 
2.32.0

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in flush_workqueue

usb 6-1: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
usb 6-1: Direct firmware load for rtlwifi/rtl8712u.bin failed with error -2
usb 6-1: Falling back to sysfs fallback for: rtlwifi/rtl8712u.bin
usb 6-1: r8712u: Firmware request failed
============================================
WARNING: possible recursive locking detected
5.14.0-rc2-syzkaller #0 Not tainted
--------------------------------------------
kworker/0:3/3159 is trying to acquire lock:
ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0x15c/0x1750 kernel/workqueue.c:2787

but task is already holding lock:
ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2249

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock((wq_completion)events);
  lock((wq_completion)events);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by kworker/0:3/3159:
 #0: ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2249
 #1: ffffc900021d7d20 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x7e8/0x10c0 kernel/workqueue.c:2251
 #2: ffff8881467d4220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:754 [inline]
 #2: ffff8881467d4220 (&dev->mutex){....}-{3:3}, at: rtl871x_load_fw_fail drivers/staging/rtl8712/hal_init.c:43 [inline]
 #2: ffff8881467d4220 (&dev->mutex){....}-{3:3}, at: rtl871x_load_fw_cb+0x102/0x130 drivers/staging/rtl8712/hal_init.c:56
 #3: ffff8880363da220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:754 [inline]
 #3: ffff8880363da220 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1028 [inline]
 #3: ffff8880363da220 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xc1/0x7b0 drivers/base/dd.c:1229
 #4: ffff8880308211a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:754 [inline]
 #4: ffff8880308211a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1028 [inline]
 #4: ffff8880308211a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xc1/0x7b0 drivers/base/dd.c:1229

stack backtrace:
CPU: 0 PID: 3159 Comm: kworker/0:3 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events request_firmware_work_func
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
 __lock_acquire+0x2615/0x6100 kernel/locking/lockdep.c:4853
 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
 flush_workqueue+0x178/0x1750 kernel/workqueue.c:2787
 flush_scheduled_work include/linux/workqueue.h:597 [inline]
 r871xu_dev_remove+0x159/0x420 drivers/staging/rtl8712/usb_intf.c:604
 usb_unbind_interface+0x1f2/0x860 drivers/usb/core/driver.c:458
 __device_release_driver drivers/base/dd.c:1201 [inline]
 device_release_driver_internal+0x51e/0x7b0 drivers/base/dd.c:1232
 bus_remove_device+0x2fd/0x410 drivers/base/bus.c:529
 device_del+0x6e1/0xc10 drivers/base/core.c:3540
 usb_disable_device+0x407/0x800 drivers/usb/core/message.c:1419
 usb_set_configuration+0x42b/0x2100 drivers/usb/core/message.c:2027
 usb_unbind_device+0x6b/0x170 drivers/usb/core/driver.c:309
 __device_release_driver drivers/base/dd.c:1201 [inline]
 device_release_driver_internal+0x51e/0x7b0 drivers/base/dd.c:1232
 rtl871x_load_fw_fail drivers/staging/rtl8712/hal_init.c:45 [inline]
 rtl871x_load_fw_cb+0x10a/0x130 drivers/staging/rtl8712/hal_init.c:56
 request_firmware_work_func+0x175/0x250 drivers/base/firmware_loader/main.c:1081
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295


Tested on:

commit:         8cae8cd8 seq_file: disallow extremely large seq buffer..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=149905f2300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=300aea483211c875
dashboard link: https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15737b4a300000

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[Pavel Skripkin]

[-- Attachment #1: Type: text/plain, Size: 4560 bytes --]

On Tue, 20 Jul 2021 08:21:06 -0700
syzbot <syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still
> triggering an issue: possible deadlock in flush_workqueue
> 
> usb 6-1: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
> usb 6-1: Direct firmware load for rtlwifi/rtl8712u.bin failed with
> error -2 usb 6-1: Falling back to sysfs fallback for:
> rtlwifi/rtl8712u.bin usb 6-1: r8712u: Firmware request failed
> ============================================
> WARNING: possible recursive locking detected
> 5.14.0-rc2-syzkaller #0 Not tainted
> --------------------------------------------
> kworker/0:3/3159 is trying to acquire lock:
> ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at:
> flush_workqueue+0x15c/0x1750 kernel/workqueue.c:2787
> 
> but task is already holding lock:
> ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at:
> process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2249
> 
> other info that might help us debug this:
>  Possible unsafe locking scenario:
> 
>        CPU0
>        ----
>   lock((wq_completion)events);
>   lock((wq_completion)events);
> 
>  *** DEADLOCK ***
> 
>  May be due to missing lock nesting notation
> 
> 5 locks held by kworker/0:3/3159:
>  #0: ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at:
> process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2249 #1:
> ffffc900021d7d20 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at:
> process_one_work+0x7e8/0x10c0 kernel/workqueue.c:2251 #2:
> ffff8881467d4220 (&dev->mutex){....}-{3:3}, at: device_lock
> include/linux/device.h:754 [inline] #2: ffff8881467d4220
> (&dev->mutex){....}-{3:3}, at: rtl871x_load_fw_fail
> drivers/staging/rtl8712/hal_init.c:43 [inline] #2: ffff8881467d4220
> (&dev->mutex){....}-{3:3}, at: rtl871x_load_fw_cb+0x102/0x130
> drivers/staging/rtl8712/hal_init.c:56 #3: ffff8880363da220
> (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:754
> [inline] #3: ffff8880363da220 (&dev->mutex){....}-{3:3}, at:
> __device_driver_lock drivers/base/dd.c:1028 [inline] #3:
> ffff8880363da220 (&dev->mutex){....}-{3:3}, at:
> device_release_driver_internal+0xc1/0x7b0 drivers/base/dd.c:1229 #4:
> ffff8880308211a8 (&dev->mutex){....}-{3:3}, at: device_lock
> include/linux/device.h:754 [inline] #4: ffff8880308211a8
> (&dev->mutex){....}-{3:3}, at: __device_driver_lock
> drivers/base/dd.c:1028 [inline] #4: ffff8880308211a8
> (&dev->mutex){....}-{3:3}, at:
> device_release_driver_internal+0xc1/0x7b0 drivers/base/dd.c:1229
> 
> stack backtrace:
> CPU: 0 PID: 3159 Comm: kworker/0:3 Not tainted 5.14.0-rc2-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine,
> BIOS Google 01/01/2011 Workqueue: events request_firmware_work_func
> Call Trace:
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
>  __lock_acquire+0x2615/0x6100 kernel/locking/lockdep.c:4853
>  lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
>  flush_workqueue+0x178/0x1750 kernel/workqueue.c:2787
>  flush_scheduled_work include/linux/workqueue.h:597 [inline]
>  r871xu_dev_remove+0x159/0x420 drivers/staging/rtl8712/usb_intf.c:604
>  usb_unbind_interface+0x1f2/0x860 drivers/usb/core/driver.c:458
>  __device_release_driver drivers/base/dd.c:1201 [inline]
>  device_release_driver_internal+0x51e/0x7b0 drivers/base/dd.c:1232
>  bus_remove_device+0x2fd/0x410 drivers/base/bus.c:529
>  device_del+0x6e1/0xc10 drivers/base/core.c:3540
>  usb_disable_device+0x407/0x800 drivers/usb/core/message.c:1419
>  usb_set_configuration+0x42b/0x2100 drivers/usb/core/message.c:2027
>  usb_unbind_device+0x6b/0x170 drivers/usb/core/driver.c:309
>  __device_release_driver drivers/base/dd.c:1201 [inline]
>  device_release_driver_internal+0x51e/0x7b0 drivers/base/dd.c:1232
>  rtl871x_load_fw_fail drivers/staging/rtl8712/hal_init.c:45 [inline]
>  rtl871x_load_fw_cb+0x10a/0x130 drivers/staging/rtl8712/hal_init.c:56
>  request_firmware_work_func+0x175/0x250
> drivers/base/firmware_loader/main.c:1081
> process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
> worker_thread+0xac1/0x1320 kernel/workqueue.c:2422
> kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30
> arch/x86/entry/entry_64.S:295
> 


Hmm, did't notice this could happen. From my point of view,
flush_scheduled_work() can be replaced with flush_work() for all
scheduled works in this driver.



#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master



 
With regards,
Pavel Skripkin

[-- Attachment #2: 0001-staging-rtl8712-rewrite-error-handling.patch --]
[-- Type: text/x-patch, Size: 6385 bytes --]

From c308b591df7d984b2b17c8cbd578907d152b9930 Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Tue, 20 Jul 2021 14:05:02 +0300
Subject: [PATCH] staging: rtl8712: rewrite error handling

/* .... */

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/staging/rtl8712/hal_init.c        | 30 ++++++++-----
 drivers/staging/rtl8712/rtl8712_led.c     |  8 ++++
 drivers/staging/rtl8712/rtl871x_led.h     |  1 +
 drivers/staging/rtl8712/rtl871x_pwrctrl.c |  8 ++++
 drivers/staging/rtl8712/rtl871x_pwrctrl.h |  1 +
 drivers/staging/rtl8712/usb_intf.c        | 51 ++++++++++-------------
 6 files changed, 61 insertions(+), 38 deletions(-)

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 22974277afa0..4eff3fdecdb8 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -29,21 +29,31 @@
 #define FWBUFF_ALIGN_SZ 512
 #define MAX_DUMP_FWSZ (48 * 1024)
 
+static void rtl871x_load_fw_fail(struct _adapter *adapter)
+{
+	struct usb_device *udev = adapter->dvobjpriv.pusbdev;
+	struct device *dev = &udev->dev;
+	struct device *parent = dev->parent;
+
+	complete(&adapter->rtl8712_fw_ready);
+
+	dev_err(&udev->dev, "r8712u: Firmware request failed\n");
+
+	if (parent)
+		device_lock(parent);
+
+	device_release_driver(dev);
+
+	if (parent)
+		device_unlock(parent);
+}
+
 static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
 {
 	struct _adapter *adapter = context;
 
 	if (!firmware) {
-		struct usb_device *udev = adapter->dvobjpriv.pusbdev;
-		struct usb_interface *usb_intf = adapter->pusb_intf;
-
-		dev_err(&udev->dev, "r8712u: Firmware request failed\n");
-		usb_put_dev(udev);
-		usb_set_intfdata(usb_intf, NULL);
-		r8712_free_drv_sw(adapter);
-		adapter->dvobj_deinit(adapter);
-		complete(&adapter->rtl8712_fw_ready);
-		free_netdev(adapter->pnetdev);
+		rtl871x_load_fw_fail(adapter);
 		return;
 	}
 	adapter->fw = firmware;
diff --git a/drivers/staging/rtl8712/rtl8712_led.c b/drivers/staging/rtl8712/rtl8712_led.c
index 5901026949f2..d5fc9026b036 100644
--- a/drivers/staging/rtl8712/rtl8712_led.c
+++ b/drivers/staging/rtl8712/rtl8712_led.c
@@ -1820,3 +1820,11 @@ void LedControl871x(struct _adapter *padapter, enum LED_CTL_MODE LedAction)
 		break;
 	}
 }
+
+void r8712_flush_led_works(struct _adapter *padapter)
+{
+	struct led_priv *pledpriv = &padapter->ledpriv;
+
+	flush_work(&pledpriv->SwLed0.BlinkWorkItem);
+	flush_work(&pledpriv->SwLed1.BlinkWorkItem);
+}
diff --git a/drivers/staging/rtl8712/rtl871x_led.h b/drivers/staging/rtl8712/rtl871x_led.h
index ee19c873cf01..2f0768132ad8 100644
--- a/drivers/staging/rtl8712/rtl871x_led.h
+++ b/drivers/staging/rtl8712/rtl871x_led.h
@@ -112,6 +112,7 @@ struct led_priv {
 void r8712_InitSwLeds(struct _adapter *padapter);
 void r8712_DeInitSwLeds(struct _adapter *padapter);
 void LedControl871x(struct _adapter *padapter, enum LED_CTL_MODE LedAction);
+void r8712_flush_led_works(struct _adapter *padapter);
 
 #endif
 
diff --git a/drivers/staging/rtl8712/rtl871x_pwrctrl.c b/drivers/staging/rtl8712/rtl871x_pwrctrl.c
index 23cff43437e2..cd6d9ff0bebc 100644
--- a/drivers/staging/rtl8712/rtl871x_pwrctrl.c
+++ b/drivers/staging/rtl8712/rtl871x_pwrctrl.c
@@ -224,3 +224,11 @@ void r8712_unregister_cmd_alive(struct _adapter *padapter)
 	}
 	mutex_unlock(&pwrctrl->mutex_lock);
 }
+
+void r8712_flush_rwctrl_works(struct _adapter *padapter)
+{
+	struct pwrctrl_priv *pwrctrl = &padapter->pwrctrlpriv;
+
+	flush_work(&pwrctrl->SetPSModeWorkItem);
+	flush_work(&pwrctrl->rpwm_workitem);
+}
diff --git a/drivers/staging/rtl8712/rtl871x_pwrctrl.h b/drivers/staging/rtl8712/rtl871x_pwrctrl.h
index bf6623cfaf27..b35b9c7920eb 100644
--- a/drivers/staging/rtl8712/rtl871x_pwrctrl.h
+++ b/drivers/staging/rtl8712/rtl871x_pwrctrl.h
@@ -108,5 +108,6 @@ void r8712_cpwm_int_hdl(struct _adapter *padapter,
 void r8712_set_ps_mode(struct _adapter *padapter, uint ps_mode,
 			uint smart_ps);
 void r8712_set_rpwm(struct _adapter *padapter, u8 val8);
+void r8712_flush_rwctrl_works(struct _adapter *padapter);
 
 #endif  /* __RTL871X_PWRCTRL_H_ */
diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index 2434b13c8b12..505ebeb643dc 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -591,35 +591,30 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
 {
 	struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
 	struct usb_device *udev = interface_to_usbdev(pusb_intf);
+	struct _adapter *padapter = netdev_priv(pnetdev);
+
+	/* never exit with a firmware callback pending */
+	wait_for_completion(&padapter->rtl8712_fw_ready);
+	usb_set_intfdata(pusb_intf, NULL);
+	release_firmware(padapter->fw);
+	if (drvpriv.drv_registered)
+		padapter->surprise_removed = true;
+	if (pnetdev->reg_state != NETREG_UNINITIALIZED)
+		unregister_netdev(pnetdev); /* will call netdev_close() */
+	r8712_flush_rwctrl_works(padapter);
+	r8712_flush_led_works(padapter);
+	udelay(1);
+	/* Stop driver mlme relation timer */
+	r8712_stop_drv_timers(padapter);
+	r871x_dev_unload(padapter);
+	r8712_free_drv_sw(padapter);
+	free_netdev(pnetdev);
+
+	/* decrease the reference count of the usb device structure
+	 * when disconnect
+	 */
+	usb_put_dev(udev);
 
-	if (pnetdev) {
-		struct _adapter *padapter = netdev_priv(pnetdev);
-
-		/* never exit with a firmware callback pending */
-		wait_for_completion(&padapter->rtl8712_fw_ready);
-		pnetdev = usb_get_intfdata(pusb_intf);
-		usb_set_intfdata(pusb_intf, NULL);
-		if (!pnetdev)
-			goto firmware_load_fail;
-		release_firmware(padapter->fw);
-		if (drvpriv.drv_registered)
-			padapter->surprise_removed = true;
-		if (pnetdev->reg_state != NETREG_UNINITIALIZED)
-			unregister_netdev(pnetdev); /* will call netdev_close() */
-		flush_scheduled_work();
-		udelay(1);
-		/* Stop driver mlme relation timer */
-		r8712_stop_drv_timers(padapter);
-		r871x_dev_unload(padapter);
-		r8712_free_drv_sw(padapter);
-		free_netdev(pnetdev);
-
-		/* decrease the reference count of the usb device structure
-		 * when disconnect
-		 */
-		usb_put_dev(udev);
-	}
-firmware_load_fail:
 	/* If we didn't unplug usb dongle and remove/insert module, driver
 	 * fails on sitesurvey for the first time when device is up.
 	 * Reset usb port for sitesurvey fail issue.
-- 
2.32.0

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: sleeping function called from invalid context in lock_sock_nested

BUG: sleeping function called from invalid context at net/core/sock.c:3161
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 8824, name: syz-executor.2
1 lock held by syz-executor.2/8824:
 #0: ffffffff8d89c920 (hci_sk_list.lock){++++}-{2:2}, at: hci_sock_dev_event+0x2b6/0x630 net/bluetooth/hci_sock.c:763
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 PID: 8824 Comm: syz-executor.2 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1d3/0x29f lib/dump_stack.c:105
 ___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9154
 lock_sock_nested+0x34/0x110 net/core/sock.c:3161
 lock_sock include/net/sock.h:1613 [inline]
 hci_sock_dev_event+0x30a/0x630 net/bluetooth/hci_sock.c:765
 hci_unregister_dev+0x487/0x19b0 net/bluetooth/hci_core.c:4033
 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x352/0x7b0 fs/file_table.c:280
 task_work_run+0x146/0x1c0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x72b/0x2510 kernel/exit.c:825
 do_group_exit+0x168/0x2d0 kernel/exit.c:922
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:933
 __se_sys_exit_group+0x10/0x10 kernel/exit.c:931
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: Unable to access opcode bytes at RIP 0x4665af.
RSP: 002b:00007ffe15e4abc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ffe15e4b388 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffe15e4b388
R10: 00000000ffffffff R11: 0000000000000246 R12: 00000000004bef54
R13: 0000000000000010 R14: 0000000000000000 R15: 0000000000400538

======================================================


Tested on:

commit:         8cae8cd8 seq_file: disallow extremely large seq buffer..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=161182ea300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=300aea483211c875
dashboard link: https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13c31a5a300000

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[Pavel Skripkin]

[-- Attachment #1: Type: text/plain, Size: 812 bytes --]

On Tue, 20 Jul 2021 15:10:08 -0700
syzbot <syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still
> triggering an issue: BUG: sleeping function called from invalid
> context in lock_sock_nested
> 
> BUG: sleeping function called from invalid context at
> net/core/sock.c:3161 in_atomic(): 1, irqs_disabled(): 0, non_block:
> 0, pid: 8824, name: syz-executor.2 1 lock held by syz-executor.2/8824:
>  #0: ffffffff8d89c920 (hci_sk_list.lock){++++}-{2:2}, at:
> hci_sock_dev_event+0x2b6/0x630 net/bluetooth/hci_sock.c:763


Ok, it is not related to my fix. Picking up Tetsuo patch to get
Reported-and-tested tag. 


#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


With regards,
Pavel Skripkin

[-- Attachment #2: 2patches.patch --]
[-- Type: text/x-patch, Size: 7388 bytes --]

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 22974277afa0..4eff3fdecdb8 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -29,21 +29,31 @@
 #define FWBUFF_ALIGN_SZ 512
 #define MAX_DUMP_FWSZ (48 * 1024)
 
+static void rtl871x_load_fw_fail(struct _adapter *adapter)
+{
+	struct usb_device *udev = adapter->dvobjpriv.pusbdev;
+	struct device *dev = &udev->dev;
+	struct device *parent = dev->parent;
+
+	complete(&adapter->rtl8712_fw_ready);
+
+	dev_err(&udev->dev, "r8712u: Firmware request failed\n");
+
+	if (parent)
+		device_lock(parent);
+
+	device_release_driver(dev);
+
+	if (parent)
+		device_unlock(parent);
+}
+
 static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
 {
 	struct _adapter *adapter = context;
 
 	if (!firmware) {
-		struct usb_device *udev = adapter->dvobjpriv.pusbdev;
-		struct usb_interface *usb_intf = adapter->pusb_intf;
-
-		dev_err(&udev->dev, "r8712u: Firmware request failed\n");
-		usb_put_dev(udev);
-		usb_set_intfdata(usb_intf, NULL);
-		r8712_free_drv_sw(adapter);
-		adapter->dvobj_deinit(adapter);
-		complete(&adapter->rtl8712_fw_ready);
-		free_netdev(adapter->pnetdev);
+		rtl871x_load_fw_fail(adapter);
 		return;
 	}
 	adapter->fw = firmware;
diff --git a/drivers/staging/rtl8712/rtl8712_led.c b/drivers/staging/rtl8712/rtl8712_led.c
index 5901026949f2..d5fc9026b036 100644
--- a/drivers/staging/rtl8712/rtl8712_led.c
+++ b/drivers/staging/rtl8712/rtl8712_led.c
@@ -1820,3 +1820,11 @@ void LedControl871x(struct _adapter *padapter, enum LED_CTL_MODE LedAction)
 		break;
 	}
 }
+
+void r8712_flush_led_works(struct _adapter *padapter)
+{
+	struct led_priv *pledpriv = &padapter->ledpriv;
+
+	flush_work(&pledpriv->SwLed0.BlinkWorkItem);
+	flush_work(&pledpriv->SwLed1.BlinkWorkItem);
+}
diff --git a/drivers/staging/rtl8712/rtl871x_led.h b/drivers/staging/rtl8712/rtl871x_led.h
index ee19c873cf01..2f0768132ad8 100644
--- a/drivers/staging/rtl8712/rtl871x_led.h
+++ b/drivers/staging/rtl8712/rtl871x_led.h
@@ -112,6 +112,7 @@ struct led_priv {
 void r8712_InitSwLeds(struct _adapter *padapter);
 void r8712_DeInitSwLeds(struct _adapter *padapter);
 void LedControl871x(struct _adapter *padapter, enum LED_CTL_MODE LedAction);
+void r8712_flush_led_works(struct _adapter *padapter);
 
 #endif
 
diff --git a/drivers/staging/rtl8712/rtl871x_pwrctrl.c b/drivers/staging/rtl8712/rtl871x_pwrctrl.c
index 23cff43437e2..cd6d9ff0bebc 100644
--- a/drivers/staging/rtl8712/rtl871x_pwrctrl.c
+++ b/drivers/staging/rtl8712/rtl871x_pwrctrl.c
@@ -224,3 +224,11 @@ void r8712_unregister_cmd_alive(struct _adapter *padapter)
 	}
 	mutex_unlock(&pwrctrl->mutex_lock);
 }
+
+void r8712_flush_rwctrl_works(struct _adapter *padapter)
+{
+	struct pwrctrl_priv *pwrctrl = &padapter->pwrctrlpriv;
+
+	flush_work(&pwrctrl->SetPSModeWorkItem);
+	flush_work(&pwrctrl->rpwm_workitem);
+}
diff --git a/drivers/staging/rtl8712/rtl871x_pwrctrl.h b/drivers/staging/rtl8712/rtl871x_pwrctrl.h
index bf6623cfaf27..b35b9c7920eb 100644
--- a/drivers/staging/rtl8712/rtl871x_pwrctrl.h
+++ b/drivers/staging/rtl8712/rtl871x_pwrctrl.h
@@ -108,5 +108,6 @@ void r8712_cpwm_int_hdl(struct _adapter *padapter,
 void r8712_set_ps_mode(struct _adapter *padapter, uint ps_mode,
 			uint smart_ps);
 void r8712_set_rpwm(struct _adapter *padapter, u8 val8);
+void r8712_flush_rwctrl_works(struct _adapter *padapter);
 
 #endif  /* __RTL871X_PWRCTRL_H_ */
diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index 2434b13c8b12..505ebeb643dc 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -591,35 +591,30 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
 {
 	struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
 	struct usb_device *udev = interface_to_usbdev(pusb_intf);
+	struct _adapter *padapter = netdev_priv(pnetdev);
+
+	/* never exit with a firmware callback pending */
+	wait_for_completion(&padapter->rtl8712_fw_ready);
+	usb_set_intfdata(pusb_intf, NULL);
+	release_firmware(padapter->fw);
+	if (drvpriv.drv_registered)
+		padapter->surprise_removed = true;
+	if (pnetdev->reg_state != NETREG_UNINITIALIZED)
+		unregister_netdev(pnetdev); /* will call netdev_close() */
+	r8712_flush_rwctrl_works(padapter);
+	r8712_flush_led_works(padapter);
+	udelay(1);
+	/* Stop driver mlme relation timer */
+	r8712_stop_drv_timers(padapter);
+	r871x_dev_unload(padapter);
+	r8712_free_drv_sw(padapter);
+	free_netdev(pnetdev);
+
+	/* decrease the reference count of the usb device structure
+	 * when disconnect
+	 */
+	usb_put_dev(udev);
 
-	if (pnetdev) {
-		struct _adapter *padapter = netdev_priv(pnetdev);
-
-		/* never exit with a firmware callback pending */
-		wait_for_completion(&padapter->rtl8712_fw_ready);
-		pnetdev = usb_get_intfdata(pusb_intf);
-		usb_set_intfdata(pusb_intf, NULL);
-		if (!pnetdev)
-			goto firmware_load_fail;
-		release_firmware(padapter->fw);
-		if (drvpriv.drv_registered)
-			padapter->surprise_removed = true;
-		if (pnetdev->reg_state != NETREG_UNINITIALIZED)
-			unregister_netdev(pnetdev); /* will call netdev_close() */
-		flush_scheduled_work();
-		udelay(1);
-		/* Stop driver mlme relation timer */
-		r8712_stop_drv_timers(padapter);
-		r871x_dev_unload(padapter);
-		r8712_free_drv_sw(padapter);
-		free_netdev(pnetdev);
-
-		/* decrease the reference count of the usb device structure
-		 * when disconnect
-		 */
-		usb_put_dev(udev);
-	}
-firmware_load_fail:
 	/* If we didn't unplug usb dongle and remove/insert module, driver
 	 * fails on sitesurvey for the first time when device is up.
 	 * Reset usb port for sitesurvey fail issue.
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index b04a5a02ecf3..786a06a232fd 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -760,10 +760,18 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event)
 		struct sock *sk;
 
 		/* Detach sockets from device */
+restart:
 		read_lock(&hci_sk_list.lock);
 		sk_for_each(sk, &hci_sk_list.head) {
+			/* This sock_hold(sk) is safe, for bt_sock_unlink(sk)
+			 * is not called yet.
+			 */
+			sock_hold(sk);
+			read_unlock(&hci_sk_list.lock);
 			lock_sock(sk);
-			if (hci_pi(sk)->hdev == hdev) {
+			write_lock(&hci_sk_list.lock);
+			/* Check that bt_sock_unlink(sk) is not called yet. */
+			if (sk_hashed(sk) && hci_pi(sk)->hdev == hdev) {
 				hci_pi(sk)->hdev = NULL;
 				sk->sk_err = EPIPE;
 				sk->sk_state = BT_OPEN;
@@ -771,7 +779,27 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event)
 
 				hci_dev_put(hdev);
 			}
+			write_unlock(&hci_sk_list.lock);
 			release_sock(sk);
+			read_lock(&hci_sk_list.lock);
+			/* If bt_sock_unlink(sk) is not called yet, we can
+			 * continue iteration. We can use __sock_put(sk) here
+			 * because hci_sock_release() will call sock_put(sk)
+			 * after bt_sock_unlink(sk).
+			 */
+			if (sk_hashed(sk)) {
+				__sock_put(sk);
+				continue;
+			}
+			/* Otherwise, we need to restart iteration, for the
+			 * next socket pointed by sk->next might be already
+			 * gone. We can't use __sock_put(sk) here because
+			 * hci_sock_release() might have already called
+			 * sock_put(sk) after bt_sock_unlink(sk).
+			 */
+			read_unlock(&hci_sk_list.lock);
+			sock_put(sk);
+			goto restart;
 		}
 		read_unlock(&hci_sk_list.lock);
 	}

Re: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com

Tested on:

commit:         8cae8cd8 seq_file: disallow extremely large seq buffer..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=300aea483211c875
dashboard link: https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1174d0d4300000

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