Leon Romanovsky <[email protected]> writes: > On Fri, Jul 17, 2026 at 11:34:20PM +0530, Aneesh Kumar K.V (Arm) wrote: >> atomic_pool_expand() frees the allocated pages from the remove_mapping >> error path only when CONFIG_DMA_DIRECT_REMAP is enabled. >> >> When CONFIG_DMA_DIRECT_REMAP is disabled, failures after page allocation, >> such as gen_pool_add_virt(), jump to remove_mapping and return without >> freeing the pages. >> >> Move __free_pages(page, order) out of the CONFIG_DMA_DIRECT_REMAP block so >> that cleanup paths always release the allocation. >> >> Reviewed-by: Jason Gunthorpe <[email protected]> >> Tested-by: Michael Kelley <[email protected]> >> Tested-by: Mostafa Saleh <[email protected]> >> Signed-off-by: Aneesh Kumar K.V (Arm) <[email protected]> >> --- >> kernel/dma/pool.c | 10 +++++++--- >> 1 file changed, 7 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c >> index 2b2fbb709242..b0303efbc153 100644 >> --- a/kernel/dma/pool.c >> +++ b/kernel/dma/pool.c >> @@ -81,6 +81,7 @@ static int atomic_pool_expand(struct gen_pool *pool, >> size_t pool_size, >> { >> unsigned int order; >> struct page *page = NULL; >> + bool leak_pages = false; >> void *addr; >> int ret = -ENOMEM; >> >> @@ -115,8 +116,10 @@ static int atomic_pool_expand(struct gen_pool *pool, >> size_t pool_size, >> */ >> ret = set_memory_decrypted((unsigned long)page_to_virt(page), >> 1 << order); >> - if (ret) >> + if (ret) { >> + leak_pages = true; >> goto remove_mapping; >> + } >> ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), >> pool_size, NUMA_NO_NODE); >> if (ret) >> @@ -130,14 +133,15 @@ static int atomic_pool_expand(struct gen_pool *pool, >> size_t pool_size, >> 1 << order); >> if (WARN_ON_ONCE(ret)) { >> /* Decrypt succeeded but encrypt failed, purposely leak */ >> - goto out; >> + leak_pages = true; > > Instead of doing this dance with temporal variable, change "goto out" to > be "return true". >
I didn't follow the return true part. A failure in set_memory_encrypted() or set_memory_decrypted() requires the pages to be leaked, so this is not the only call site that sets leak_pages = true. There is a similar case a few lines above. > >> } >> remove_mapping: >> #ifdef CONFIG_DMA_DIRECT_REMAP >> dma_common_free_remap(addr, pool_size); >> free_page: > > Remove free_page label, and change leftover of "goto free_page" to be > "goto out" > >> - __free_pages(page, order); >> #endif >> + if (!leak_pages) >> + __free_pages(page, order); > > Put these checks under out label and rely on page != NULL as a marker. > if (page) > __free_pages(page, order); > >> out: >> return ret; >> } >> -- >> 2.43.0 >> >> -aneesh
