From 22f4bb68b301f4ab896e9b3b0431fdde962242d2 Mon Sep 17 00:00:00 2001 From: Manuel Lauss Date: Tue, 26 Jan 2010 20:39:33 +0100 Subject: [PATCH] MIPS: Alchemy: Fix dbdma ring destruction memory debugcheck. DBDMA descriptors need to be located at 32-byte aligned addresses; however kmalloc in conjunction with the SLAB allocator and CONFIG_DEBUG_SLUB enabled doesn't deliver any. The dbdma code works around that by allocating a larger area and realigning the start address within it. When freeing a channel however this adjustment is not taken into account which results in an oops: Kernel bug detected[#1]: [...] Call Trace: [<80186010>] cache_free_debugcheck+0x284/0x318 [<801869d8>] kfree+0xe8/0x2a0 [<8010b31c>] au1xxx_dbdma_chan_free+0x2c/0x7c [<80388dc8>] au1x_pcm_dbdma_free+0x34/0x4c [<80388fa8>] au1xpsc_pcm_close+0x28/0x38 [<80383cb8>] soc_codec_close+0x14c/0x1cc [<8036dbb4>] snd_pcm_release_substream+0x60/0xac [<8036dc40>] snd_pcm_release+0x40/0xa0 [<8018c7a8>] __fput+0x11c/0x228 [<80188f60>] filp_close+0x7c/0x98 [<80189018>] sys_close+0x9c/0xe4 [<801022a0>] stack_done+0x20/0x3c Fix this by recording the address delivered by kmalloc() and using it as parameter to kfree(). This fix is only necessary with the SLAB allocator and CONFIG_DEBUG_SLAB enabled; non-debug SLAB, SLUB do return nicely aligned addresses, debug-enabled SLUB currently panics early in the boot process. Signed-off-by: Manuel Lauss To: Linux-MIPS Cc: Manuel Lauss Patchwork: http://patchwork.linux-mips.org/patch/878/ Signed-off-by: Ralf Baechle --- arch/mips/alchemy/common/dbdma.c | 7 +++++-- arch/mips/include/asm/mach-au1x00/au1xxx_dbdma.h | 1 + 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/mips/alchemy/common/dbdma.c b/arch/mips/alchemy/common/dbdma.c index 5c68569..f9201ca 100644 --- a/arch/mips/alchemy/common/dbdma.c +++ b/arch/mips/alchemy/common/dbdma.c @@ -412,8 +412,11 @@ u32 au1xxx_dbdma_ring_alloc(u32 chanid, int entries) if (desc_base == 0) return 0; + ctp->cdb_membase = desc_base; desc_base = ALIGN_ADDR(desc_base, sizeof(au1x_ddma_desc_t)); - } + } else + ctp->cdb_membase = desc_base; + dp = (au1x_ddma_desc_t *)desc_base; /* Keep track of the base descriptor. */ @@ -831,7 +834,7 @@ void au1xxx_dbdma_chan_free(u32 chanid) au1xxx_dbdma_stop(chanid); - kfree((void *)ctp->chan_desc_base); + kfree((void *)ctp->cdb_membase); stp->dev_flags &= ~DEV_FLAGS_INUSE; dtp->dev_flags &= ~DEV_FLAGS_INUSE; diff --git a/arch/mips/include/asm/mach-au1x00/au1xxx_dbdma.h b/arch/mips/include/asm/mach-au1x00/au1xxx_dbdma.h index 06f68f4..d206000 100644 --- a/arch/mips/include/asm/mach-au1x00/au1xxx_dbdma.h +++ b/arch/mips/include/asm/mach-au1x00/au1xxx_dbdma.h @@ -305,6 +305,7 @@ typedef struct dbdma_chan_config { dbdev_tab_t *chan_dest; au1x_dma_chan_t *chan_ptr; au1x_ddma_desc_t *chan_desc_base; + u32 cdb_membase; /* kmalloc base of above */ au1x_ddma_desc_t *get_ptr, *put_ptr, *cur_ptr; void *chan_callparam; void (*chan_callback)(int, void *); -- 2.7.4