Hi, I managed to hit this on a screwy setup (bad interrupt routing). Its the sym2 driver. It looks like the error handler thread freed the same sgtable twice. Second time through we mempool_free on a NULL pointer and die. Anton 0:0:0:0: ABORT operation started. 0:0:0:0: ABORT operation timed-out. 0:0:0:0: DEVICE RESET operation started. 0:0:0:0: DEVICE RESET operation timed-out. 0:0:0:0: BUS RESET operation started. 0:0:0:0: BUS RESET operation timed-out. 0:0:0:0: HOST RESET operation started. sym0: SCSI BUS has been reset. 0:0:0:0: HOST RESET operation timed-out. scsi: Device offlined - not ready after error recovery: host 0 channel 0 id 0 lun 0 scsi_free_sgtable sgp c0000000006679e0 sgl c00000000fc18c80 Call Trace: [c000000000338c60] scsi_io_completion+0x250/0x520 [c00000000032fe34] scsi_finish_command+0xa4/0x130 [c0000000003363cc] scsi_error_handler+0x65c/0xb20 [c000000000071558] kthread+0x178/0x190 scsi_free_sgtable sgp c0000000006679e0 sgl 0 Call Trace: [c00000000033734c] scsi_release_buffers+0x8c/0xc0 [c0000000003373c8] scsi_unprep_request+0x48/0x70 [c0000000003386a8] scsi_requeue_command+0x28/0x80 [c000000000338da8] scsi_io_completion+0x398/0x520 [c00000000032fe34] scsi_finish_command+0xa4/0x130 [c0000000003363cc] scsi_error_handler+0x65c/0xb20 [c000000000071558] kthread+0x178/0x190 cpu 0x0: Vector: 300 (Data Access) at [c000000003ddf5c0] pc: c000000000096d14: .kmem_cache_free+0x64/0x230 lr: c00000000008e7ac: .mempool_free_slab+0x1c/0x30 dar: c0000040bfff3fc0 <---- this is the bad address pid = 752, comm = scsi_eh_0 - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html