Re: [PATCH-RESEND] cxl: Disable prefault_mode in Radix mode
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-05-29 01:18:38
Also in:
stable
Vaibhav Jain [off-list ref] writes:
quoted hunk ↗ jump to hunk
From: Vaibhav Jain <redacted> Currently we see a kernel-oops reported on Power-9 while attaching a context to an AFU, with radix-mode and sysfs attr 'prefault_mode' set to anything other than 'none'. The backtrace of the oops is of this form: Unable to handle kernel paging request for data at address 0x00000080 Faulting instruction address: 0xc00800000bcf3b20 cpu 0x1: Vector: 300 (Data Access) at [c00000037f003800] pc: c00800000bcf3b20: cxl_load_segment+0x178/0x290 [cxl] lr: c00800000bcf39f0: cxl_load_segment+0x48/0x290 [cxl] sp: c00000037f003a80 msr: 9000000000009033 dar: 80 dsisr: 40000000 current = 0xc00000037f280000 paca = 0xc0000003ffffe600 softe: 3 irq_happened: 0x01 pid = 3529, comm = afp_no_int <snip> [c00000037f003af0] c00800000bcf4424 cxl_prefault+0xfc/0x248 [cxl] [c00000037f003b50] c00800000bcf8a40 process_element_entry_psl9+0xd8/0x1a0 [cxl] [c00000037f003b90] c00800000bcf944c cxl_attach_dedicated_process_psl9+0x44/0x130 [cxl] [c00000037f003bd0] c00800000bcf5448 native_attach_process+0xc0/0x130 [cxl] [c00000037f003c50] c00800000bcf16cc afu_ioctl+0x3f4/0x5e0 [cxl] [c00000037f003d00] c00000000039d98c do_vfs_ioctl+0xdc/0x890 [c00000037f003da0] c00000000039e1a8 ksys_ioctl+0x68/0xf0 [c00000037f003df0] c00000000039e270 sys_ioctl+0x40/0xa0 [c00000037f003e30] c00000000000b320 system_call+0x58/0x6c--- Exception: c01 (System Call) at 0000000010053bb0
^^^ This tells patch/git-am to drop the rest of the change log, which is not what we want. I tend to indent stack traces etc with two spaces, which avoids the problem. Or in this case we can just drop the line as it's not really that informative. I've fixed it up. cheers