Subject: Re: [PATCH 1/2] sh_eth: Fix sleeping function called from invalid context

From: Sergei Shtylyov <[email-masked]>
Date: Tue, 25 Nov 2014 14:02:34 +0300

Hello.

On 11/25/2014 5:17 AM, Simon Horman wrote:

>>> From: Mitsuhiro Kimura <[email-masked]>

>>> Fix the bug as follows:

>>> ----
>>> [ 1238.161349] BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:952
>>> [ 1238.188279] in_atomic(): 1, irqs_disabled(): 0, pid: 1388, name: cat
>>> [ 1238.207425] CPU: 0 PID: 1388 Comm: cat Not tainted 3.10.31-ltsi-00046-gefa0b46 #1087
>>> [ 1238.230737] Backtrace:
>>> [ 1238.238123] [<c0012e64>] (dump_backtrace+0x0/0x10c) from [<c0013000>] (show_stack+0x18/0x1c)
>>> [ 1238.263499]  r6:000003b8 r5:c06160c0 r4:c0669e00 r3:00404000
>>> [ 1238.280583] [<c0012fe8>] (show_stack+0x0/0x1c) from [<c04515a4>] (dump_stack+0x20/0x28)
>>> [ 1238.304631] [<c0451584>] (dump_stack+0x0/0x28) from [<c004970c>] (__might_sleep+0xf8/0x118)
>>> [ 1238.329734] [<c0049614>] (__might_sleep+0x0/0x118) from [<c02465ac>] (__pm_runtime_resume+0x38/0x90)
>>> [ 1238.357170]  r7:d616f000 r6:c049c458 r5:00000004 r4:d6a17210
>>> [ 1238.374251] [<c0246574>] (__pm_runtime_resume+0x0/0x90) from [<c029b1c4>] (sh_eth_get_stats+0x44/0x280)
>>> [ 1238.402468]  r7:d616f000 r6:c049c458 r5:d5c21000 r4:d5c21000
>>> [ 1238.419552] [<c029b180>] (sh_eth_get_stats+0x0/0x280) from [<c03ae39c>] (dev_get_stats+0x54/0x88)
>>> [ 1238.446204]  r5:d5c21000 r4:d5ed7e08
>>> [ 1238.456980] [<c03ae348>] (dev_get_stats+0x0/0x88) from [<c03c677c>] (netstat_show.isra.15+0x54/0x9c)
>>> [ 1238.484413]  r6:d5c21000 r5:d5c21238 r4:00000028 r3:00000001
>>> [ 1238.501495] [<c03c6728>] (netstat_show.isra.15+0x0/0x9c) from [<c03c69b8>] (show_tx_errors+0x18/0x1c)
>>> [ 1238.529196]  r7:d5f945d8 r6:d5f945c0 r5:c049716c r4:c0650e7c
>>> [ 1238.546279] [<c03c69a0>] (show_tx_errors+0x0/0x1c) from [<c023963c>] (dev_attr_show+0x24/0x50)
>>> [ 1238.572157] [<c0239618>] (dev_attr_show+0x0/0x50) from [<c010c148>] (sysfs_read_file+0xb0/0x140)
>>> [ 1238.598554]  r5:c049716c r4:d5c21240
>>> [ 1238.609326] [<c010c098>] (sysfs_read_file+0x0/0x140) from [<c00b9ee4>] (vfs_read+0xb0/0x13c)
>>> [ 1238.634679] [<c00b9e34>] (vfs_read+0x0/0x13c) from [<c00ba0ac>] (SyS_read+0x44/0x74)
>>> [ 1238.657944]  r8:bef45bf0 r7:00000000 r6:d6ac0600 r5:00000000 r4:00000000
>>> [ 1238.678172] [<c00ba068>] (SyS_read+0x0/0x74) from [<c000eec0>] (ret_fast_syscall+0x0/0x30)
>>> ----

>>     How to reproduce this?

> I have spoken with Kimura-san and the problem may be reproduced by
> building the kernel with CONFIG_DEBUG_ATOMIC_SLEEP=y and reading network
> statistics while the network interface is down.

> e.g.:

> ifconfig eth0 down
> cat /sys/class/net/eth0/statistics/tx_errors

> I have confirmed that the problem above appears in net-next
> and appears to be resolved by this patch.

    Shouldn't we target 'net' for the fixes instead?

> Would you be happy with this patch if the changelog was enhanced
> and the minor issue you point our below was resolved?

    Most probably yes.

>>> Signed-off-by: Mitsuhiro Kimura <[email-masked]>
>>> Signed-off-by: Yoshihiro Kaneko <[email-masked]>

[...]

WBR, Sergei