diff options
| author | Michael J. Ruhl <michael.j.ruhl@intel.com> | 2020-07-23 21:15:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-07-24 12:42:42 -0700 |
| commit | e0b3e0b1a04367fc15c07f44e78361545b55357c (patch) | |
| tree | bdab613c6f73fc82f6adfbfb1bbece9eb37331a2 | |
| parent | d178770d8d21489abf5bafefcbb6d5243b482e9a (diff) | |
| download | lwn-e0b3e0b1a04367fc15c07f44e78361545b55357c.tar.gz lwn-e0b3e0b1a04367fc15c07f44e78361545b55357c.zip | |
io-mapping: indicate mapping failure
The !ATOMIC_IOMAP version of io_maping_init_wc will always return
success, even when the ioremap fails.
Since the ATOMIC_IOMAP version returns NULL when the init fails, and
callers check for a NULL return on error this is unexpected.
During a device probe, where the ioremap failed, a crash can look like
this:
BUG: unable to handle page fault for address: 0000000000210000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
Oops: 0002 [#1] PREEMPT SMP
CPU: 0 PID: 177 Comm:
RIP: 0010:fill_page_dma [i915]
gen8_ppgtt_create [i915]
i915_ppgtt_create [i915]
intel_gt_init [i915]
i915_gem_init [i915]
i915_driver_probe [i915]
pci_device_probe
really_probe
driver_probe_device
The remap failure occurred much earlier in the probe. If it had been
propagated, the driver would have exited with an error.
Return NULL on ioremap failure.
[akpm@linux-foundation.org: detect ioremap_wc() errors earlier]
Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping")
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200721171936.81563-1-michael.j.ruhl@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/io-mapping.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index 0beaa3eba155..c75e4d3d8833 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -107,9 +107,12 @@ io_mapping_init_wc(struct io_mapping *iomap, resource_size_t base, unsigned long size) { + iomap->iomem = ioremap_wc(base, size); + if (!iomap->iomem) + return NULL; + iomap->base = base; iomap->size = size; - iomap->iomem = ioremap_wc(base, size); #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */ iomap->prot = pgprot_noncached_wc(PAGE_KERNEL); #elif defined(pgprot_writecombine) |