From 8f2777f53e3d5ad8ef2a176a4463a5c8e1a16431 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 5 Jun 2015 14:20:51 -0700 Subject: [PATCH] libfc: Fix fc_fcp_cleanup_each_cmd() Since fc_fcp_cleanup_cmd() can sleep this function must not be called while holding a spinlock. This patch avoids that fc_fcp_cleanup_each_cmd() triggers the following bug: BUG: scheduling while atomic: sg_reset/1512/0x00000202 1 lock held by sg_reset/1512: #0: (&(&fsp->scsi_pkt_lock)->rlock){+.-...}, at: [] fc_fcp_cleanup_each_cmd.isra.21+0xa5/0x150 [libfc] Preemption disabled at:[] fc_fcp_cleanup_each_cmd.isra.21+0xa5/0x150 [libfc] Call Trace: [] dump_stack+0x4f/0x7b [] __schedule_bug+0x6c/0xd0 [] __schedule+0x71a/0xa10 [] schedule+0x32/0x80 [] fc_seq_set_resp+0xac/0x100 [libfc] [] fc_exch_done+0x41/0x60 [libfc] [] fc_fcp_cleanup_each_cmd.isra.21+0xcf/0x150 [libfc] [] fc_eh_device_reset+0x1c3/0x270 [libfc] [] scsi_try_bus_device_reset+0x29/0x60 [] scsi_ioctl_reset+0x258/0x2d0 [] scsi_ioctl+0x150/0x440 [] sd_ioctl+0xad/0x120 [] blkdev_ioctl+0x1b6/0x810 [] block_ioctl+0x38/0x40 [] do_vfs_ioctl+0x2f8/0x530 [] SyS_ioctl+0x81/0xa0 [] system_call_fastpath+0x16/0x7a Signed-off-by: Bart Van Assche Cc: stable Signed-off-by: Vasu Dev Signed-off-by: James Bottomley --- drivers/scsi/libfc/fc_fcp.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index c679594..2d5909c 100644 --- a/drivers/scsi/libfc/fc_fcp.c +++ b/drivers/scsi/libfc/fc_fcp.c @@ -1039,11 +1039,26 @@ restart: fc_fcp_pkt_hold(fsp); spin_unlock_irqrestore(&si->scsi_queue_lock, flags); - if (!fc_fcp_lock_pkt(fsp)) { + spin_lock_bh(&fsp->scsi_pkt_lock); + if (!(fsp->state & FC_SRB_COMPL)) { + fsp->state |= FC_SRB_COMPL; + /* + * TODO: dropping scsi_pkt_lock and then reacquiring + * again around fc_fcp_cleanup_cmd() is required, + * since fc_fcp_cleanup_cmd() calls into + * fc_seq_set_resp() and that func preempts cpu using + * schedule. May be schedule and related code should be + * removed instead of unlocking here to avoid scheduling + * while atomic bug. + */ + spin_unlock_bh(&fsp->scsi_pkt_lock); + fc_fcp_cleanup_cmd(fsp, error); + + spin_lock_bh(&fsp->scsi_pkt_lock); fc_io_compl(fsp); - fc_fcp_unlock_pkt(fsp); } + spin_unlock_bh(&fsp->scsi_pkt_lock); fc_fcp_pkt_release(fsp); spin_lock_irqsave(&si->scsi_queue_lock, flags); -- 2.7.4