linux-kernel - Re: [RFC] floppy: use single threaded workqueue

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100721195547.GA3448@amt.cnet>
Date:	Wed, 21 Jul 2010 16:55:47 -0300
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Stephen Hemminger <shemminger@...tta.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC] floppy: use single threaded workqueue

On Fri, Jun 11, 2010 at 10:32:23AM -0700, Stephen Hemminger wrote:
> Fix races between timers and bottom half by using delayed work
> and a single threaded queue.
> 
> Still needs more testing.
> 
> Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
> 
> ---
>  drivers/block/floppy.c |  172 ++++++++++++++++++++++++++-----------------------
>  1 file changed, 94 insertions(+), 78 deletions(-)

Stephen,

Can confirm this fixes the following oops seen under KVM guests.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000035
IP: [<ffffffff812141f0>] setup_rw_floppy+0x229/0x2ca
PGD 284b8067 PUD 3d79f067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:03.0/resource
CPU 1
Modules linked in: xt_tcpudp iptable_filter ip_tables x_tables
scsi_wait_scan uhci_hcd ohci_hcd ehci_hcd

Pid: 28, comm: events/1 Not tainted 2.6.35-rc5-35033-g14e84ff #221
/Bochs RIP: 0010:[<ffffffff812141f0>]  [<ffffffff812141f0>] setup_rw_floppy+0x229/0x2ca
RSP: 0018:ffff88003e1a1e60  EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000286 RDI: 0000000000000000
RBP: 00000000000000da R08: 0000000000000000 R09: ffffffff81214bdb
R10: 0000000000000000 R11: ffffffff817f7660 R12: 0000000000000000
R13: 0000000000000008 R14: ffffffff81214bdb R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff880001a40000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000035 CR3: 000000003a428000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process events/1 (pid: 28, threadinfo ffff88003e1a0000, task
ffff88003e19a8f0)
Stack:
 0000000000000000 ffff88003e1a1ef8 ffffffff81692f00 ffff880001a56680
<0> ffff88003e19a8f0 ffffffff810466f1 0000000000000000 ffff88003e19a8f0
<0> ffffffff810495ad ffff88003e1a1ea8 ffff88003e1a1ea8 ffff88003e1a1ef8
Call Trace:
 [<ffffffff810466f1>] ? worker_thread+0x150/0x1f0
 [<ffffffff810495ad>] ? autoremove_wake_function+0x0/0x2e
 [<ffffffff810465a1>] ? worker_thread+0x0/0x1f0
 [<ffffffff810492bf>] ? kthread+0x79/0x81
 [<ffffffff81002be4>] ? kernel_thread_helper+0x4/0x10


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/