From: Bart Van Assche <bart.vanass...@sandisk.com> 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: [<ffffffffc0225cd5>] fc_fcp_cleanup_each_cmd.isra.21+0xa5/0x150 [libfc] Preemption disabled at:[<ffffffffc0225cd5>] fc_fcp_cleanup_each_cmd.isra.21+0xa5/0x150 [libfc] Call Trace: [<ffffffff816c612c>] dump_stack+0x4f/0x7b [<ffffffff810828bc>] __schedule_bug+0x6c/0xd0 [<ffffffff816c87aa>] __schedule+0x71a/0xa10 [<ffffffff816c8ad2>] schedule+0x32/0x80 [<ffffffffc0217eac>] fc_seq_set_resp+0xac/0x100 [libfc] [<ffffffffc0218b11>] fc_exch_done+0x41/0x60 [libfc] [<ffffffffc0225cff>] fc_fcp_cleanup_each_cmd.isra.21+0xcf/0x150 [libfc] [<ffffffffc0225f43>] fc_eh_device_reset+0x1c3/0x270 [libfc] [<ffffffff814a2cc9>] scsi_try_bus_device_reset+0x29/0x60 [<ffffffff814a3908>] scsi_ioctl_reset+0x258/0x2d0 [<ffffffff814a2650>] scsi_ioctl+0x150/0x440 [<ffffffff814b3a9d>] sd_ioctl+0xad/0x120 [<ffffffff8132f266>] blkdev_ioctl+0x1b6/0x810 [<ffffffff811da608>] block_ioctl+0x38/0x40 [<ffffffff811b4e08>] do_vfs_ioctl+0x2f8/0x530 [<ffffffff811b50c1>] SyS_ioctl+0x81/0xa0 [<ffffffff816cf8b2>] system_call_fastpath+0x16/0x7a Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com> Cc: stable <sta...@vger.kernel.org> [ Added TODO notes to fix by removing entire schedule() code flow as discussed here at: http://lists.open-fcoe.org/pipermail/fcoe-devel/2015-May/012471.html ] Signed-off-by: Vasu Dev <vasu....@intel.com> --- drivers/scsi/libfc/fc_fcp.c | 19 +++++++++++++++++-- 1 files changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index 4cd49d4..5121272 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); -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html