On Tue, May 19, 2020 at 04:24:10PM -0300, Marcelo Ricardo Leitner wrote: > On Tue, May 19, 2020 at 11:51:23AM +0300, Jere Leppänen wrote: > > On Thu, 30 Apr 2020, Marcelo Ricardo Leitner wrote: > > > > > On Wed, Apr 29, 2020 at 07:36:13AM -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@xxxxxxxxxxxxx> > > > > CC: Vlad Yasevich <vyasevich@xxxxxxxxx> > > > > CC: "David S. Miller" <davem@xxxxxxxxxxxxx> > > > > CC: Jere Leppänen <jere.leppanen@xxxxxxxxx> > > > > CC: marcelo.leitner@xxxxxxxxx > > > > > > > > --- > > > > Change notes: > > > > V2) Updated to use timer_reduce > > > > > > Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> > > > > Hey is this patch falling through the cracks again? No rush, I'm just > > wondering what's going on. > > Whoops, sounds like Neil forgot to Cc netdev@.. > > Marcelo > Crap, my bad. I'm stuck in a call at the moment, but I'll resend this tomorrow morning. Thanks for following up! Neil
