From 0368dfd01ae3b7647ef9b2f0525fdefd5e0d28e1 Mon Sep 17 00:00:00 2001 From: "Lad, Prabhakar" Date: Wed, 29 Jan 2014 14:05:37 -0800 Subject: [PATCH] lib/genalloc.c: add check gen_pool_dma_alloc() if dma pointer is not NULL In the gen_pool_dma_alloc() the dma pointer can be NULL and while assigning gen_pool_virt_to_phys(pool, vaddr) to dma caused the following crash on da850 evm: Unable to handle kernel NULL pointer dereference at virtual address 00000000 Internal error: Oops: 805 [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.13.0-rc1-00001-g0609e45-dirty #5 task: c4830000 ti: c4832000 task.ti: c4832000 PC is at gen_pool_dma_alloc+0x30/0x3c LR is at gen_pool_virt_to_phys+0x74/0x80 Process swapper, call trace: gen_pool_dma_alloc+0x30/0x3c davinci_pm_probe+0x40/0xa8 platform_drv_probe+0x1c/0x4c driver_probe_device+0x98/0x22c __driver_attach+0x8c/0x90 bus_for_each_dev+0x6c/0x8c bus_add_driver+0x124/0x1d4 driver_register+0x78/0xf8 platform_driver_probe+0x20/0xa4 davinci_init_late+0xc/0x14 init_machine_late+0x1c/0x28 do_one_initcall+0x34/0x15c kernel_init_freeable+0xe4/0x1ac kernel_init+0x8/0xec This patch fixes the above. [akpm@linux-foundation.org: update kerneldoc] Signed-off-by: Lad, Prabhakar Cc: Philipp Zabel Cc: Nicolin Chen Cc: Joe Perches Cc: Sachin Kamat Cc: [3.13.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/genalloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/genalloc.c b/lib/genalloc.c index dda3116..bdb9a45 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -316,7 +316,7 @@ EXPORT_SYMBOL(gen_pool_alloc); * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage * @pool: pool to allocate from * @size: number of bytes to allocate from the pool - * @dma: dma-view physical address + * @dma: dma-view physical address return value. Use NULL if unneeded. * * Allocate the requested number of bytes from the specified pool. * Uses the pool allocation function (with first-fit algorithm by default). @@ -334,7 +334,8 @@ void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma) if (!vaddr) return NULL; - *dma = gen_pool_virt_to_phys(pool, vaddr); + if (dma) + *dma = gen_pool_virt_to_phys(pool, vaddr); return (void *)vaddr; } -- 2.7.4