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| author | Jan Kara <jack@suse.cz> | 2012-07-31 16:41:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-31 18:42:39 -0700 |
| commit | aa91c4d898c062804f4d0a5da6d8ab013cd0e868 (patch) | |
| tree | b4472de48394ca8aafac72e2e97eb9a259fd8111 /mm/vmalloc.c | |
| parent | 92ca922f0a19145f2dcc99d84fe656fa55b52c2e (diff) | |
| download | lwn-aa91c4d898c062804f4d0a5da6d8ab013cd0e868.tar.gz lwn-aa91c4d898c062804f4d0a5da6d8ab013cd0e868.zip | |
mm: make vb_alloc() more foolproof
If someone calls vb_alloc() (or vm_map_ram() for that matter) to allocate
0 bytes (0 pages), get_order() returns BITS_PER_LONG - PAGE_CACHE_SHIFT
and interesting stuff happens. So make debugging such problems easier and
warn about 0-size allocation.
[akpm@linux-foundation.org: use WARN_ON-return-value feature]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 7e25ee3ce6e5..2bb90b1d241c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -904,6 +904,14 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) BUG_ON(size & ~PAGE_MASK); BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); + if (WARN_ON(size == 0)) { + /* + * Allocating 0 bytes isn't what caller wants since + * get_order(0) returns funny result. Just warn and terminate + * early. + */ + return NULL; + } order = get_order(size); again: |