On Sun, Jul 21, 2019 at 11:01 PM Ming Lei <tom.leiming@xxxxxxxxx> wrote: > > On Tue, Jun 18, 2019 at 4:57 AM Bart Van Assche <bvanassche@xxxxxxx> wrote: > > > > On 6/17/19 5:19 AM, Christoph Hellwig wrote: > > > We need to limit the devices max_sectors to what the DMA mapping > > > implementation can support. If not we risk running out of swiotlb > > > buffers easily. > > > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > > --- > > > drivers/scsi/scsi_lib.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > > > index d333bb6b1c59..f233bfd84cd7 100644 > > > --- a/drivers/scsi/scsi_lib.c > > > +++ b/drivers/scsi/scsi_lib.c > > > @@ -1768,6 +1768,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) > > > blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); > > > } > > > > > > + shost->max_sectors = min_t(unsigned int, shost->max_sectors, > > > + dma_max_mapping_size(dev) << SECTOR_SHIFT); > > > blk_queue_max_hw_sectors(q, shost->max_sectors); > > > if (shost->unchecked_isa_dma) > > > blk_queue_bounce_limit(q, BLK_BOUNCE_ISA); > > > > Does dma_max_mapping_size() return a value in bytes? Is > > shost->max_sectors a number of sectors? If so, are you sure that "<< > > SECTOR_SHIFT" is the proper conversion? Shouldn't that be ">> > > SECTOR_SHIFT" instead? > > Now the patch has been committed, '<< SECTOR_SHIFT' needs to be fixed. > > Also the following kernel oops is triggered on qemu, and looks > device->dma_mask is NULL. > > Ming Lei FYI: we also see the panic with a Linux kernel 5.2.0-next-20190719 running on Hyper-V: [ 7.429053] RIP: 0010:dma_direct_max_mapping_size+0x26/0x80 [ 7.429053] Code: 0f b6 c0 c3 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb e8 4c 14 00 00 84 c0 74 45 48 8b 83 28 02 00 00 4c 8b a3 38 02 00 00 <48> 8b 00 48 85 c0 74 0c 4d 85 e4 74 36 49 39 c4 4c 0f 47 e0 48 89 [ 7.429053] RSP: 0018:ffffc1d5005efbc0 EFLAGS: 00010202 [ 7.429053] RAX: 0000000000000000 RBX: ffff9cf86d24c428 RCX: 0000000000000000 [ 7.429053] RDX: ffff9cf86d12dd00 RSI: 0000000000000200 RDI: ffff9cf86d24c428 [ 7.429053] RBP: ffffc1d5005efbd0 R08: ffff9cf86fcaf0e0 R09: ffff9cf86e0072c0 [ 7.429053] R10: ffffc1d5005efa70 R11: 00000000000301a0 R12: 0000000000000000 [ 7.429053] R13: ffff9cf86d24c428 R14: 0000000000000400 R15: ffff9cf825cff000 [ 7.429053] FS: 0000000000000000(0000) GS:ffff9cf86fc80000(0000) knlGS:0000000000000000 [ 7.429053] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7.429053] CR2: 0000000000000000 CR3: 00000003c700a001 CR4: 00000000003606e0 [ 7.456569] NET: Registered protocol family 17 [ 7.429053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 7.469803] Key type dns_resolver registered [ 7.429053] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 7.429053] Call Trace: [ 7.429053] dma_max_mapping_size+0x39/0x50 [ 7.429053] __scsi_init_queue+0x7f/0x140 [ 7.429053] scsi_mq_alloc_queue+0x38/0x60 [ 7.429053] scsi_alloc_sdev+0x1da/0x2b0 [ 7.429053] scsi_probe_and_add_lun+0x471/0xe60 [ 7.429053] __scsi_scan_target+0xfc/0x610 [ 7.429053] scsi_scan_channel+0x66/0xa0 [ 7.429053] scsi_scan_host_selected+0xf3/0x160 [ 7.429053] do_scsi_scan_host+0x93/0xa0 [ 7.429053] do_scan_async+0x1c/0x190 [ 7.429053] async_run_entry_fn+0x3c/0x150 [ 7.429053] process_one_work+0x1f7/0x3f0 [ 7.429053] worker_thread+0x34/0x400 [ 7.429053] kthread+0x121/0x140 [ 7.429053] ret_from_fork+0x35/0x40 [ 7.429053] Modules linked in: [ 7.429053] CR2: 0000000000000000 [ 7.766122] BUG: kernel NULL pointer dereference, address: 0000000000000000 Thanks, -- Dexuan
