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>
