Hi Christoph, On 03/02/20 7:51 PM, Christoph Hellwig wrote: > On Fri, Jan 31, 2020 at 05:14:01PM +0530, Kishon Vijay Abraham I wrote: >>> Can you throw in a little debug printk if this comes from >>> dma_direct_possible or swiotlb_map? >> >> I could see swiotlb_tbl_map_single() returning DMA_MAPPING_ERROR. >> >> Kernel with debug print: >> https://github.com/kishon/linux-wip.git nvm_dma_issue >> >> Full log: https://pastebin.ubuntu.com/p/Xf2ngxc3kB/ > > Ok, this mostly like means we allocate a swiotlb buffer that isn't > actually addressable. To verify that can you post the output with the > first attached patch? If it shows the overflow message added there, > please try if the second patch fixes it. I'm seeing some sort of busy loop after applying your 1st patch. I sent a SysRq to see where it is stuck [ 182.641398] sysrq: Show Blocked State [ 182.645080] task PC stack pid father [ 182.650359] sync D 0 2101 1901 0x00000000 [ 182.655889] [<c0a399b8>] (__schedule) from [<c0a39e54>] (schedule+0xa0/0x138) [ 182.663063] [<c0a39e54>] (schedule) from [<c0a3a484>] (io_schedule+0x14/0x34) [ 182.670237] [<c0a3a484>] (io_schedule) from [<c02eebec>] (wait_on_page_bit+0x14c/0x1a8) [ 182.678283] [<c02eebec>] (wait_on_page_bit) from [<c02edaa4>] (__filemap_fdatawait_range+0x94/0xec) [ 182.687374] [<c02edaa4>] (__filemap_fdatawait_range) from [<c02edb8c>] (filemap_fdatawait_keep_errors+0x24/0x50) [ 182.697601] [<c02edb8c>] (filemap_fdatawait_keep_errors) from [<c0385a84>] (sync_inodes_sb+0x1a8/0x23c) [ 182.707041] [<c0385a84>] (sync_inodes_sb) from [<c035bd84>] (iterate_supers+0x88/0xdc) [ 182.714998] [<c035bd84>] (iterate_supers) from [<c0389be4>] (ksys_sync+0x40/0xb8) [ 182.722519] [<c0389be4>] (ksys_sync) from [<c0389c64>] (sys_sync+0x8/0x10) [ 182.729429] [<c0389c64>] (sys_sync) from [<c0201000>] (ret_fast_syscall+0x0/0x4c) [ 182.736943] Exception stack(0xe5461fa8 to 0xe5461ff0) [ 182.742016] 1fa0: be8a8db4 be8a8db8 00000000 ffffffff 00000000 0009d6b8 [ 182.750230] 1fc0: be8a8db4 be8a8db8 00000001 00000024 be8a8db4 00000000 b6f0b000 0009d6dc [ 182.758443] 1fe0: b6e2e3d0 be8a8c1c 00064821 b6e2e3dc Full log here: https://pastebin.ubuntu.com/p/q6yDtP9vxR/ Thanks Kishon >
