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| author | Takashi Iwai <tiwai@suse.de> | 2018-07-19 12:01:04 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-07-23 10:06:33 +0300 |
| commit | dfef01e150824b0e6da750cacda8958188d29aea (patch) | |
| tree | 0718893e1055b764ffc89f6ca2673478ba791533 /sound/core/memalloc.c | |
| parent | f3d737b6340b0c7bacd8bc751605f0ed6203f146 (diff) | |
| download | linux-dfef01e150824b0e6da750cacda8958188d29aea.tar.xz | |
ALSA: memalloc: Don't exceed over the requested size
snd_dma_alloc_pages_fallback() tries to allocate pages again when the
allocation fails with reduced size. But the first try actually
*increases* the size to power-of-two, which may give back a larger
chunk than the requested size. This confuses the callers, e.g. sgbuf
assumes that the size is equal or less, and it may result in a bad
loop due to the underflow and eventually lead to Oops.
The code of this function seems incorrectly assuming the usage of
get_order(). We need to decrease at first, then align to
power-of-two.
Reported-and-tested-by: he, bo <bo.he@intel.com>
Reported-by: zhang jun <jun.zhang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/memalloc.c')
| -rw-r--r-- | sound/core/memalloc.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 7f89d3c79a4b..753d5fc4b284 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -242,16 +242,12 @@ int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size, int err; while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) { - size_t aligned_size; if (err != -ENOMEM) return err; if (size <= PAGE_SIZE) return -ENOMEM; - aligned_size = PAGE_SIZE << get_order(size); - if (size != aligned_size) - size = aligned_size; - else - size >>= 1; + size >>= 1; + size = PAGE_SIZE << get_order(size); } if (! dmab->area) return -ENOMEM; |