Hi, Steven
Thanks for your reply!
I'm using kernel3.4. The function uid_stat_tcp_rcv() was added by below patch:
Yes, this file was removed in kernel3.8. So to avoid this happen, we should always avoid this lock used in softirq context in future right?
And for kernel3.4, what's your opinion to do this fix?
commit 5a0b3548945769cf631a21e769f14a9ba8ae1c99
Author: Mike Chan <mike@xxxxxxxxxxx>
Date: Wed Jan 7 11:40:42 2009 -0800
misc: uidstat: Adding uid stat driver to collect network statistics.
Signed-off-by: Mike Chan <mike@xxxxxxxxxxx>
Thanks!
Best Regards
Lisa Du
-----Original Message-----
From: Steven Rostedt [mailto:rostedt@xxxxxxxxxxx]
Sent: 2013年5月22日 1:39
To: Lisa Du
Cc: linux-fsdevel@xxxxxxxxxxxxxxx; Ingo Molnar
Subject: Re: proc_subdir_lock related deadlock
On Sun, 2013-05-19 at 22:12 -0700, Lisa Du wrote:
> Dear Sir
> Recently I met a deadlock case which is caused by proc_subdir_lock used in softirq context.
> So I searched the mailing list and find there’s already the discussion in 2006 as below:
> http://lkml.indiana.edu/hypermail/linux/kernel/0601.3/0437.html
> And I also checked the mainline, seems no direct fix patch for this potential issue.
> So I want to know if there’s any concern that mainline didn’t accept the patch?
I believe the real fix is not to call remove or create proc from softirq
context.
What kernel are you using, as I can't find uid_stat_tcp_rcv() anywhere
in the latest kernel.
-- Steve
> Looking forward to your reply and thanks in advance!
>
> BTW: below are the soft lockup panic stack I have got:
> #0 [<c0181b98>] (crash_update) from [<c0135980>]
> #1 [<c0135980>] (panic_flush) from [<c015b454>]
> #2 [<c015b454>] (notifier_call_chain) from [<c015b618>]
> #3 [<c015b618>] (__atomic_notifier_call_chain) from [<c015b63c>]
> #4 [<c015b63c>] (atomic_notifier_call_chain) from [<c05c323c>]
> #5 [<c05c323c>] (panic) from [<c0183278>]
> #6 [<c0183278>] (watchdog_timer_fn) from [<c01598c8>]
> #7 [<c01598c8>] (__run_hrtimer) from [<c015a4fc>]
> #8 [<c015a4fc>] (hrtimer_interrupt) from [<c01183c0>]
> #9 [<c01183c0>] (twd_handler) from [<c0186c60>]
> #10 [<c0186c60>] (handle_percpu_devid_irq) from [<c0183894>]
> #11 [<c0183894>] (generic_handle_irq) from [<c0113c9c>]
> #12 [<c0113c9c>] (handle_IRQ) from [<c01084ac>]
> #13 [<c01084ac>] (gic_handle_irq) from [<c0112980>]
> pc : [<c05c9e90>] lr : [<c05c9e68>] psr: 20000113
> sp : dc831780 ip : 00000000 fp : 000003d8
> r10: c4180ad0 r9 : c05757dc r8 : dc831828
> r7 : 00000002 r6 : 00000001 r5 : dc830000 r4 : c08b7294
> r3 : 00000001 r2 : dc831770 r1 : 00000000 r0 : 00000001
> Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM
> #14 [<c0112980>] (__irq_svc) from [<c05c9e68>]
> #15 [<c05c9e90>] (__raw_spin_lock) from [<c021ef7c>]
> #16 [<c021ef7c>] (__proc_create) from [<c021f1b8>]
> #17 [<c021f1b8>] (proc_mkdir_mode) from [<c034fcc4>]
> #18 [<c034fcc4>] (create_stat) from [<c034fdb4>]
> #19 [<c034fdb4>] (uid_stat_tcp_rcv) from [<c04bf498>]
> #20 [<c04bf498>] (tcp_read_sock) from [<c0575478>]
> #21 [<c0575478>] (xs_tcp_data_ready) from [<c04c7c48>]
> #22 [<c04c7c48>] (tcp_rcv_established) from [<c04cdba4>]
> #23 [<c04cdba4>] (tcp_v4_do_rcv) from [<c04cfb24>]
> #24 [<c04cfb24>] (tcp_v4_rcv) from [<c04b0ac8>]
> #25 [<c04b0ac8>] (ip_local_deliver_finish) from [<c04b0940>]
> #26 [<c04b0940>] (ip_rcv_finish) from [<c0479974>]
> #27 [<c0479974>] (__netif_receive_skb) from [<c0479b5c>]
> #28 [<c0479b5c>] (process_backlog) from [<c047ccc8>]
> #29 [<c047ccc8>] (net_rx_action) from [<c013f9b8>]
> #30 [<c013f9b8>] (__do_softirq) from [<c013ff00>]
> #31 [<c013ff00>] (irq_exit) from [<c0113ca0>]
> #32 [<c0113ca0>] (handle_IRQ) from [<c01084ac>]
> #33 [<c01084ac>] (gic_handle_irq) from [<c0112980>]
> pc : [<c02e7294>] lr : [<c021ee08>] psr: 20000113
> sp : dc831a48 ip : 005f7000 fp : 00000000
> r10: c8145e74 r9 : 60000113 r8 : 60000113
> r7 : d216c8d5 r6 : c8171180 r5 : c8170f00 r4 : d216c880
> r3 : 00000073 r2 : 00000067 r1 : d216c8d6 r0 : c81711d6
> Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM
> #34 [<c0112980>] (__irq_svc) from [<c021ee08>]
> #35 [<c02e7294>] (strcmp) from [<c021ee08>]
> #36 [<c021ee08>] (proc_register) from [<c021f1cc>]
> #37 [<c021f1cc>] (proc_mkdir_mode) from [<c0188540>]
> #38 [<c0188540>] (register_handler_proc) from [<c01853b8>]
> #39 [<c01853b8>] (__setup_irq) from [<c0185530>]
> #40 [<c0185530>] (request_threaded_irq) from [<bf000388>]
> #41 [<bf000388>] (gckGALDEVICE_Setup_ISR [galcore]) from [<bf0334a0>]
> #42 [<bf0334a0>] (gckHARDWARE_SetPowerManagementState [galcore]) from [<bf00f840>]
> #43 [<bf00f840>] (gckOS_Broadcast [galcore]) from [<bf019988>]
> #44 [<bf019988>] (gckCOMMAND_EnterCommit [galcore]) from [<bf01a52c>]
> #45 [<bf01a52c>] (gckCOMMAND_Commit [galcore]) from [<bf017518>]
> #46 [<bf017518>] (gckKERNEL_Dispatch [galcore]) from [<bf002190>]
> #47 [<bf002190>] (drv_ioctl [galcore]) from [<c01e5c84>]
> #48 [<c01e5c84>] (do_vfs_ioctl) from [<c01e5d2c>]
> #49 [<c01e5d2c>] (sys_ioctl) from [<c0112d80>]
>
> Thanks!
>
> Best Regards
> Lisa Du
>
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