From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: linux-sctp@vger.kernel.org, Vlad Yasevich <vyasevich@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
jere.leppanen@nokia.com, netdev@vger.kernel.org
Subject: Re: [PATCH] sctp: Don't add the shutdown timer if its already been added
Date: Tue, 19 May 2020 17:43:22 -0300 [thread overview]
Message-ID: <20200519204322.GR2491@localhost.localdomain> (raw)
In-Reply-To: <20200519200405.857632-1-nhorman@tuxdriver.com>
On Tue, May 19, 2020 at 04:04:05PM -0400, Neil Horman wrote:
> This BUG halt was reported a while back, but the patch somehow got
> missed:
>
> PID: 2879 TASK: c16adaa0 CPU: 1 COMMAND: "sctpn"
> #0 [f418dd28] crash_kexec at c04a7d8c
> #1 [f418dd7c] oops_end at c0863e02
> #2 [f418dd90] do_invalid_op at c040aaca
> #3 [f418de28] error_code (via invalid_op) at c08631a5
> EAX: f34baac0 EBX: 00000090 ECX: f418deb0 EDX: f5542950 EBP: 00000000
> DS: 007b ESI: f34ba800 ES: 007b EDI: f418dea0 GS: 00e0
> CS: 0060 EIP: c046fa5e ERR: ffffffff EFLAGS: 00010286
> #4 [f418de5c] add_timer at c046fa5e
> #5 [f418de68] sctp_do_sm at f8db8c77 [sctp]
> #6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp]
> #7 [f418df48] inet_shutdown at c080baf9
> #8 [f418df5c] sys_shutdown at c079eedf
> #9 [f418df70] sys_socketcall at c079fe88
> EAX: ffffffda EBX: 0000000d ECX: bfceea90 EDX: 0937af98
> DS: 007b ESI: 0000000c ES: 007b EDI: b7150ae4
> SS: 007b ESP: bfceea7c EBP: bfceeaa8 GS: 0033
> CS: 0073 EIP: b775c424 ERR: 00000066 EFLAGS: 00000282
>
> It appears that the side effect that starts the shutdown timer was processed
> multiple times, which can happen as multiple paths can trigger it. This of
> course leads to the BUG halt in add_timer getting called.
>
> Fix seems pretty straightforward, just check before the timer is added if its
> already been started. If it has mod the timer instead to min(current
> expiration, new expiration)
>
> Its been tested but not confirmed to fix the problem, as the issue has only
> occured in production environments where test kernels are enjoined from being
> installed. It appears to be a sane fix to me though. Also, recentely,
> Jere found a reproducer posted on list to confirm that this resolves the
> issues
>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> CC: Vlad Yasevich <vyasevich@gmail.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: jere.leppanen@nokia.com
> CC: marcelo.leitner@gmail.com
> CC: netdev@vger.kernel.org
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
next prev parent reply other threads:[~2020-05-19 20:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 20:04 [PATCH] sctp: Don't add the shutdown timer if its already been added Neil Horman
2020-05-19 20:43 ` Marcelo Ricardo Leitner [this message]
2020-05-19 22:48 ` David Miller
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