From 6094628bfd94323fc1cea05ec2c6affd98c18f7f Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Wed, 2 Mar 2011 06:28:22 +0000 Subject: [PATCH] rds: prevent BUG_ON triggering on congestion map updates Recently had this bug halt reported to me: kernel BUG at net/rds/send.c:329! Oops: Exception in kernel mode, sig: 5 [#1] SMP NR_CPUS=1024 NUMA pSeries Modules linked in: rds sunrpc ipv6 dm_mirror dm_region_hash dm_log ibmveth sg ext4 jbd2 mbcache sd_mod crc_t10dif ibmvscsic scsi_transport_srp scsi_tgt dm_mod [last unloaded: scsi_wait_scan] NIP: d000000003ca68f4 LR: d000000003ca67fc CTR: d000000003ca8770 REGS: c000000175cab980 TRAP: 0700 Not tainted (2.6.32-118.el6.ppc64) MSR: 8000000000029032 CR: 44000022 XER: 00000000 TASK = c00000017586ec90[1896] 'krdsd' THREAD: c000000175ca8000 CPU: 0 GPR00: 0000000000000150 c000000175cabc00 d000000003cb7340 0000000000002030 GPR04: ffffffffffffffff 0000000000000030 0000000000000000 0000000000000030 GPR08: 0000000000000001 0000000000000001 c0000001756b1e30 0000000000010000 GPR12: d000000003caac90 c000000000fa2500 c0000001742b2858 c0000001742b2a00 GPR16: c0000001742b2a08 c0000001742b2820 0000000000000001 0000000000000001 GPR20: 0000000000000040 c0000001742b2814 c000000175cabc70 0800000000000000 GPR24: 0000000000000004 0200000000000000 0000000000000000 c0000001742b2860 GPR28: 0000000000000000 c0000001756b1c80 d000000003cb68e8 c0000001742b27b8 NIP [d000000003ca68f4] .rds_send_xmit+0x4c4/0x8a0 [rds] LR [d000000003ca67fc] .rds_send_xmit+0x3cc/0x8a0 [rds] Call Trace: [c000000175cabc00] [d000000003ca67fc] .rds_send_xmit+0x3cc/0x8a0 [rds] (unreliable) [c000000175cabd30] [d000000003ca7e64] .rds_send_worker+0x54/0x100 [rds] [c000000175cabdb0] [c0000000000b475c] .worker_thread+0x1dc/0x3c0 [c000000175cabed0] [c0000000000baa9c] .kthread+0xbc/0xd0 [c000000175cabf90] [c000000000032114] .kernel_thread+0x54/0x70 Instruction dump: 4bfffd50 60000000 60000000 39080001 935f004c f91f0040 41820024 813d017c 7d094a78 7d290074 7929d182 394a0020 <0b090000> 40e2ff68 4bffffa4 39200000 Kernel panic - not syncing: Fatal exception Call Trace: [c000000175cab560] [c000000000012e04] .show_stack+0x74/0x1c0 (unreliable) [c000000175cab610] [c0000000005a365c] .panic+0x80/0x1b4 [c000000175cab6a0] [c00000000002fbcc] .die+0x21c/0x2a0 [c000000175cab750] [c000000000030000] ._exception+0x110/0x220 [c000000175cab910] [c000000000004b9c] program_check_common+0x11c/0x180 Signed-off-by: David S. Miller --- net/rds/ib_send.c | 5 ++++- net/rds/loop.c | 11 ++++++++--- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c index 71f373c421bc..c47a511f203d 100644 --- a/net/rds/ib_send.c +++ b/net/rds/ib_send.c @@ -551,7 +551,10 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, if (conn->c_loopback && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { rds_cong_map_updated(conn->c_fcong, ~(u64) 0); - return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; + scat = &rm->data.op_sg[sg]; + ret = sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; + ret = min_t(int, ret, scat->length - conn->c_xmit_data_off); + return ret; } /* FIXME we may overallocate here */ diff --git a/net/rds/loop.c b/net/rds/loop.c index aeec1d483b17..bca6761a3ca2 100644 --- a/net/rds/loop.c +++ b/net/rds/loop.c @@ -61,10 +61,15 @@ static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, unsigned int hdr_off, unsigned int sg, unsigned int off) { + struct scatterlist *sgp = &rm->data.op_sg[sg]; + int ret = sizeof(struct rds_header) + + be32_to_cpu(rm->m_inc.i_hdr.h_len); + /* Do not send cong updates to loopback */ if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { rds_cong_map_updated(conn->c_fcong, ~(u64) 0); - return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; + ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off); + goto out; } BUG_ON(hdr_off || sg || off); @@ -80,8 +85,8 @@ static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, NULL); rds_inc_put(&rm->m_inc); - - return sizeof(struct rds_header) + be32_to_cpu(rm->m_inc.i_hdr.h_len); +out: + return ret; } /* -- 2.20.1