zram: fix use-after-free in zram_bvec_write_partial()#890
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zram: fix use-after-free in zram_bvec_write_partial()#890blktests-ci[bot] wants to merge 1 commit into
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zram_read_page() picks the sync or async backing device read path based on whether the parent bio is NULL. zram_bvec_write_partial() passes its parent bio down, so for ZRAM_WB slots the read is dispatched asynchronously and zram_read_page() returns 0 while the bio is still in flight. The caller then runs memcpy_from_bvec(), zram_write_page() and __free_page() on the buffer, leaving the async read to write into a freed page. zram_bvec_read_partial() was switched to NULL in commit 4e3c87b ("zram: fix synchronous reads") for the same reason; the write_partial counterpart was missed. Fixes: 4e3c87b ("zram: fix synchronous reads") Cc: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Signed-off-by: Cunlong Li <shenxiaogll@gmail.com>
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Pull request for series with
subject: zram: fix use-after-free in zram_bvec_write_partial()
version: 1
url: https://patchwork.kernel.org/project/linux-block/list/?series=1101344