Messages in this thread Patch in this message | | | From | Weijie Yang <> | Subject | [PATCH] zram: avoid kunmap_atomic a NULL pointer | Date | Thu, 30 Oct 2014 14:20:31 +0800 |
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zram could kunmap_atomic a NULL pointer in a rare situation: a zram page become a full-zeroed page after a partial write io. The current code doesn't handle this case and kunmap_atomic a NULL porinter, which panic the kernel.
This patch fixes this issue.
Signed-off-by: Weijie Yang <weijie.yang@samsung.com> --- drivers/block/zram/zram_drv.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 2ad0b5b..3920ee4 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -560,7 +560,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, } if (page_zero_filled(uncmem)) { - kunmap_atomic(user_mem); + if (user_mem) + kunmap_atomic(user_mem); /* Free memory associated with this sector now. */ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); zram_free_page(zram, index); -- 1.7.0.4
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