From fbd019737d71e405f86549fd738f81e2ff3dd073 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Mon, 29 Apr 2019 14:16:19 +0800 Subject: sctp: avoid running the sctp state machine recursively Ying triggered a call trace when doing an asconf testing: BUG: scheduling while atomic: swapper/12/0/0x10000100 Call Trace: [] dump_stack+0x19/0x1b [] __schedule_bug+0x64/0x72 [] __schedule+0x9ba/0xa00 [] __cond_resched+0x26/0x30 [] _cond_resched+0x3a/0x50 [] kmem_cache_alloc_node+0x38/0x200 [] __alloc_skb+0x5d/0x2d0 [] sctp_packet_transmit+0x610/0xa20 [sctp] [] sctp_outq_flush+0x2ce/0xc00 [sctp] [] sctp_outq_uncork+0x1c/0x20 [sctp] [] sctp_cmd_interpreter.isra.22+0xc8/0x1460 [sctp] [] sctp_do_sm+0xe1/0x350 [sctp] [] sctp_primitive_ASCONF+0x3d/0x50 [sctp] [] sctp_cmd_interpreter.isra.22+0x114/0x1460 [sctp] [] sctp_do_sm+0xe1/0x350 [sctp] [] sctp_assoc_bh_rcv+0xf4/0x1b0 [sctp] [] sctp_inq_push+0x51/0x70 [sctp] [] sctp_rcv+0xa8b/0xbd0 [sctp] As it shows, the first sctp_do_sm() running under atomic context (NET_RX softirq) invoked sctp_primitive_ASCONF() that uses GFP_KERNEL flag later, and this flag is supposed to be used in non-atomic context only. Besides, sctp_do_sm() was called recursively, which is not expected. Vlad tried to fix this recursive call in Commit c0786693404c ("sctp: Fix oops when sending queued ASCONF chunks") by introducing a new command SCTP_CMD_SEND_NEXT_ASCONF. But it didn't work as this command is still used in the first sctp_do_sm() call, and sctp_primitive_ASCONF() will be called in this command again. To avoid calling sctp_do_sm() recursively, we send the next queued ASCONF not by sctp_primitive_ASCONF(), but by sctp_sf_do_prm_asconf() in the 1st sctp_do_sm() directly. Reported-by: Ying Xu Signed-off-by: Xin Long Acked-by: Neil Horman Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- include/net/sctp/command.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/net/sctp/command.h') diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h index 6640f84fe536..6d5beac29bc1 100644 --- a/include/net/sctp/command.h +++ b/include/net/sctp/command.h @@ -105,7 +105,6 @@ enum sctp_verb { SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */ SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */ SCTP_CMD_SEND_MSG, /* Send the whole use message */ - SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */ SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/ SCTP_CMD_SET_ASOC, /* Restore association context */ SCTP_CMD_LAST -- cgit