From: Guillaume Ranquet <granquet@xxxxxxxxxxxx> [ Upstream commit 0a2ff58f9f8f95526ecb0ccd7517fefceb96f661 ] The desc_free handler assumed that the desc we want to free was always the current one associated with the channel. This is seldom the case and this is causing use after free crashes in multiple places (tx/rx/terminate...). BUG: KASAN: use-after-free in mtk_uart_apdma_rx_handler+0x120/0x304 Call trace: dump_backtrace+0x0/0x1b0 show_stack+0x24/0x34 dump_stack+0xe0/0x150 print_address_description+0x8c/0x55c __kasan_report+0x1b8/0x218 kasan_report+0x14/0x20 __asan_load4+0x98/0x9c mtk_uart_apdma_rx_handler+0x120/0x304 mtk_uart_apdma_irq_handler+0x50/0x80 __handle_irq_event_percpu+0xe0/0x210 handle_irq_event+0x8c/0x184 handle_fasteoi_irq+0x1d8/0x3ac __handle_domain_irq+0xb0/0x110 gic_handle_irq+0x50/0xb8 el0_irq_naked+0x60/0x6c Allocated by task 3541: __kasan_kmalloc+0xf0/0x1b0 kasan_kmalloc+0x10/0x1c kmem_cache_alloc_trace+0x90/0x2dc mtk_uart_apdma_prep_slave_sg+0x6c/0x1a0 mtk8250_dma_rx_complete+0x220/0x2e4 vchan_complete+0x290/0x340 tasklet_action_common+0x220/0x298 tasklet_action+0x28/0x34 __do_softirq+0x158/0x35c Freed by task 3541: __kasan_slab_free+0x154/0x224 kasan_slab_free+0x14/0x24 slab_free_freelist_hook+0xf8/0x15c kfree+0xb4/0x278 mtk_uart_apdma_desc_free+0x34/0x44 vchan_complete+0x1bc/0x340 tasklet_action_common+0x220/0x298 tasklet_action+0x28/0x34 __do_softirq+0x158/0x35c The buggy address belongs to the object at ffff000063606800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 176 bytes inside of 256-byte region [ffff000063606800, ffff000063606900) The buggy address belongs to the page: page:fffffe00016d8180 refcount:1 mapcount:0 mapping:ffff00000302f600 index:0x0 compound_mapcount: 0 flags: 0xffff00000010200(slab|head) raw: 0ffff00000010200 dead000000000100 dead000000000122 ffff00000302f600 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210513192642.29446-2-granquet@xxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/dma/mediatek/mtk-uart-apdma.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c index 27c07350971d..e38b67fc0c0c 100644 --- a/drivers/dma/mediatek/mtk-uart-apdma.c +++ b/drivers/dma/mediatek/mtk-uart-apdma.c @@ -131,10 +131,7 @@ static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg) static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd) { - struct dma_chan *chan = vd->tx.chan; - struct mtk_chan *c = to_mtk_uart_apdma_chan(chan); - - kfree(c->desc); + kfree(container_of(vd, struct mtk_uart_apdma_desc, vd)); } static void mtk_uart_apdma_start_tx(struct mtk_chan *c) -- 2.30.2
