tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 3a00d3dfd4b68b208ecd5405e676d06c8ad6bb63 commit: 5e1c2f7ce6aae47f3f10bbe5c4d56594aa14b3b1 [2808/2998] device-dax: add dis-contiguous resource support config: nios2-randconfig-m031-20200825 (attached as .config) compiler: nios2-linux-gcc (GCC) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> smatch warnings: drivers/dax/bus.c:626 alloc_dev_dax_range() error: potential null dereference 'alloc'. (__request_region returns null) drivers/dax/bus.c:626 alloc_dev_dax_range() error: we previously assumed 'alloc' could be null (see line 610) # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=5e1c2f7ce6aae47f3f10bbe5c4d56594aa14b3b1 git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 5e1c2f7ce6aae47f3f10bbe5c4d56594aa14b3b1 vim +/alloc +626 drivers/dax/bus.c 51cf784c42d07f Dan Williams 2017-07-12 581 6c956f1d0568d6 Dan Williams 2020-08-25 582 static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, 6c956f1d0568d6 Dan Williams 2020-08-25 583 resource_size_t size) 3774776cf2f571 Dan Williams 2020-08-25 584 { 3774776cf2f571 Dan Williams 2020-08-25 585 struct dax_region *dax_region = dev_dax->region; 3774776cf2f571 Dan Williams 2020-08-25 586 struct resource *res = &dax_region->res; 3774776cf2f571 Dan Williams 2020-08-25 587 struct device *dev = &dev_dax->dev; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 588 struct dev_dax_range *ranges; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 589 unsigned long pgoff = 0; 3774776cf2f571 Dan Williams 2020-08-25 590 struct resource *alloc; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 591 int i; 3774776cf2f571 Dan Williams 2020-08-25 592 3774776cf2f571 Dan Williams 2020-08-25 593 device_lock_assert(dax_region->dev); 3774776cf2f571 Dan Williams 2020-08-25 594 775775d41abcfd Dan Williams 2020-08-25 595 /* handle the seed alloc special case */ 775775d41abcfd Dan Williams 2020-08-25 596 if (!size) { 5e1c2f7ce6aae4 Dan Williams 2020-08-25 597 if (dev_WARN_ONCE(dev, dev_dax->nr_range, 5e1c2f7ce6aae4 Dan Williams 2020-08-25 598 "0-size allocation must be first\n")) 5e1c2f7ce6aae4 Dan Williams 2020-08-25 599 return -EBUSY; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 600 /* nr_range == 0 is elsewhere special cased as 0-size device */ 775775d41abcfd Dan Williams 2020-08-25 601 return 0; 775775d41abcfd Dan Williams 2020-08-25 602 } 775775d41abcfd Dan Williams 2020-08-25 603 5e1c2f7ce6aae4 Dan Williams 2020-08-25 604 ranges = krealloc(dev_dax->ranges, sizeof(*ranges) 5e1c2f7ce6aae4 Dan Williams 2020-08-25 605 * (dev_dax->nr_range + 1), GFP_KERNEL); 5e1c2f7ce6aae4 Dan Williams 2020-08-25 606 if (!ranges) 5e1c2f7ce6aae4 Dan Williams 2020-08-25 607 return -ENOMEM; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 608 6c956f1d0568d6 Dan Williams 2020-08-25 609 alloc = __request_region(res, start, size, dev_name(dev), 0); 5e1c2f7ce6aae4 Dan Williams 2020-08-25 @610 if (!alloc && !dev_dax->nr_range) { 5e1c2f7ce6aae4 Dan Williams 2020-08-25 611 /* 5e1c2f7ce6aae4 Dan Williams 2020-08-25 612 * If we adjusted an existing @ranges leave it alone, 5e1c2f7ce6aae4 Dan Williams 2020-08-25 613 * but if this was an empty set of ranges nothing else 5e1c2f7ce6aae4 Dan Williams 2020-08-25 614 * will release @ranges, so do it now. 5e1c2f7ce6aae4 Dan Williams 2020-08-25 615 */ 5e1c2f7ce6aae4 Dan Williams 2020-08-25 616 kfree(ranges); 3774776cf2f571 Dan Williams 2020-08-25 617 return -ENOMEM; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 618 } 3774776cf2f571 Dan Williams 2020-08-25 619 5e1c2f7ce6aae4 Dan Williams 2020-08-25 620 for (i = 0; i < dev_dax->nr_range; i++) 5e1c2f7ce6aae4 Dan Williams 2020-08-25 621 pgoff += PHYS_PFN(range_len(&ranges[i].range)); 5e1c2f7ce6aae4 Dan Williams 2020-08-25 622 dev_dax->ranges = ranges; 5e1c2f7ce6aae4 Dan Williams 2020-08-25 623 ranges[dev_dax->nr_range++] = (struct dev_dax_range) { 5e1c2f7ce6aae4 Dan Williams 2020-08-25 624 .pgoff = pgoff, 5e1c2f7ce6aae4 Dan Williams 2020-08-25 625 .range = { 3774776cf2f571 Dan Williams 2020-08-25 @626 .start = alloc->start, 3774776cf2f571 Dan Williams 2020-08-25 627 .end = alloc->end, 5e1c2f7ce6aae4 Dan Williams 2020-08-25 628 }, 3774776cf2f571 Dan Williams 2020-08-25 629 }; 3774776cf2f571 Dan Williams 2020-08-25 630 5e1c2f7ce6aae4 Dan Williams 2020-08-25 631 dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1, 5e1c2f7ce6aae4 Dan Williams 2020-08-25 632 &alloc->start, &alloc->end); 5e1c2f7ce6aae4 Dan Williams 2020-08-25 633 3774776cf2f571 Dan Williams 2020-08-25 634 return 0; 3774776cf2f571 Dan Williams 2020-08-25 635 } 3774776cf2f571 Dan Williams 2020-08-25 636 :::::: The code at line 626 was first introduced by commit :::::: 3774776cf2f571343c360204513ccef312fa339f device-dax: add an allocation interface for device-dax instances :::::: TO: Dan Williams <dan.j.williams@xxxxxxxxx> :::::: CC: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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