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authorMike Kravetz <mike.kravetz@oracle.com>2020-08-11 18:32:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-12 10:57:57 -0700
commit3a5139f1c5bb76d69756fb8f13fffa173e261153 (patch)
tree3e40508972197ae44c8cac6dc41306682f9b6b52 /mm/cma.c
parent29d0f41d232393482ced6a233126832df3429ad2 (diff)
downloadlinux-3a5139f1c5bb76d69756fb8f13fffa173e261153.tar.bz2
cma: don't quit at first error when activating reserved areas
The routine cma_init_reserved_areas is designed to activate all reserved cma areas. It quits when it first encounters an error. This can leave some areas in a state where they are reserved but not activated. There is no feedback to code which performed the reservation. Attempting to allocate memory from areas in such a state will result in a BUG. Modify cma_init_reserved_areas to always attempt to activate all areas. The called routine, cma_activate_area is responsible for leaving the area in a valid state. No one is making active use of returned error codes, so change the routine to void. How to reproduce: This example uses kernelcore, hugetlb and cma as an easy way to reproduce. However, this is a more general cma issue. Two node x86 VM 16GB total, 8GB per node Kernel command line parameters, kernelcore=4G hugetlb_cma=8G Related boot time messages, hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node cma: Reserved 4096 MiB at 0x0000000100000000 hugetlb_cma: reserved 4096 MiB on node 0 cma: Reserved 4096 MiB at 0x0000000300000000 hugetlb_cma: reserved 4096 MiB on node 1 cma: CMA area hugetlb could not be activated # echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... Call Trace: bitmap_find_next_zero_area_off+0x51/0x90 cma_alloc+0x1a5/0x310 alloc_fresh_huge_page+0x78/0x1a0 alloc_pool_huge_page+0x6f/0xf0 set_max_huge_pages+0x10c/0x250 nr_hugepages_store_common+0x92/0x120 ? __kmalloc+0x171/0x270 kernfs_fop_write+0xc1/0x1a0 vfs_write+0xc7/0x1f0 ksys_write+0x5f/0xe0 do_syscall_64+0x4d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Barry Song <song.bao.hua@hisilicon.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/cma.c')
-rw-r--r--mm/cma.c23
1 files changed, 9 insertions, 14 deletions
diff --git a/mm/cma.c b/mm/cma.c
index aa2df0bd49c3..7f415d7cda9f 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -93,17 +93,15 @@ static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
mutex_unlock(&cma->lock);
}
-static int __init cma_activate_area(struct cma *cma)
+static void __init cma_activate_area(struct cma *cma)
{
unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
unsigned i = cma->count >> pageblock_order;
struct zone *zone;
cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
- if (!cma->bitmap) {
- cma->count = 0;
- return -ENOMEM;
- }
+ if (!cma->bitmap)
+ goto out_error;
WARN_ON_ONCE(!pfn_valid(pfn));
zone = page_zone(pfn_to_page(pfn));
@@ -133,25 +131,22 @@ static int __init cma_activate_area(struct cma *cma)
spin_lock_init(&cma->mem_head_lock);
#endif
- return 0;
+ return;
not_in_zone:
- pr_err("CMA area %s could not be activated\n", cma->name);
bitmap_free(cma->bitmap);
+out_error:
cma->count = 0;
- return -EINVAL;
+ pr_err("CMA area %s could not be activated\n", cma->name);
+ return;
}
static int __init cma_init_reserved_areas(void)
{
int i;
- for (i = 0; i < cma_area_count; i++) {
- int ret = cma_activate_area(&cma_areas[i]);
-
- if (ret)
- return ret;
- }
+ for (i = 0; i < cma_area_count; i++)
+ cma_activate_area(&cma_areas[i]);
return 0;
}