[PATCH] ARM: dma-mapping: fix incorrect freeing of atomic allocations

From: Aaro Koskinen
Date: Sun Aug 05 2012 - 08:51:21 EST


Commit e9da6e9905e639b0f842a244bc770b48ad0523e9 (ARM: dma-mapping:
remove custom consistent dma region) changed the way atomic allocations
are handled. However, arm_dma_free() was not modified accordingly, and
as a result freeing of atomic allocations does not work correctly when
CMA is disabled. Memory is leaked and following WARNINGs are seen:

[ 57.698911] ------------[ cut here ]------------
[ 57.753518] WARNING: at arch/arm/mm/dma-mapping.c:263 arm_dma_free+0x88/0xe4()
[ 57.811473] trying to free invalid coherent area: e0848000
[ 57.867398] Modules linked in: sata_mv(-)
[ 57.921373] [<c000d270>] (unwind_backtrace+0x0/0xf0) from [<c0015430>] (warn_slowpath_common+0x50/0x68)
[ 58.033924] [<c0015430>] (warn_slowpath_common+0x50/0x68) from [<c00154dc>] (warn_slowpath_fmt+0x30/0x40)
[ 58.152024] [<c00154dc>] (warn_slowpath_fmt+0x30/0x40) from [<c000dc18>] (arm_dma_free+0x88/0xe4)
[ 58.219592] [<c000dc18>] (arm_dma_free+0x88/0xe4) from [<c008fa30>] (dma_pool_destroy+0x100/0x148)
[ 58.345526] [<c008fa30>] (dma_pool_destroy+0x100/0x148) from [<c019a64c>] (release_nodes+0x144/0x218)
[ 58.475782] [<c019a64c>] (release_nodes+0x144/0x218) from [<c0197e10>] (__device_release_driver+0x60/0xb8)
[ 58.614260] [<c0197e10>] (__device_release_driver+0x60/0xb8) from [<c0198608>] (driver_detach+0xd8/0xec)
[ 58.756527] [<c0198608>] (driver_detach+0xd8/0xec) from [<c0197c54>] (bus_remove_driver+0x7c/0xc4)
[ 58.901648] [<c0197c54>] (bus_remove_driver+0x7c/0xc4) from [<c004bfac>] (sys_delete_module+0x19c/0x220)
[ 59.051447] [<c004bfac>] (sys_delete_module+0x19c/0x220) from [<c0009140>] (ret_fast_syscall+0x0/0x2c)
[ 59.207996] ---[ end trace 0745420412c0325a ]---
[ 59.287110] ------------[ cut here ]------------
[ 59.366324] WARNING: at arch/arm/mm/dma-mapping.c:263 arm_dma_free+0x88/0xe4()
[ 59.450511] trying to free invalid coherent area: e0847000
[ 59.534357] Modules linked in: sata_mv(-)
[ 59.616785] [<c000d270>] (unwind_backtrace+0x0/0xf0) from [<c0015430>] (warn_slowpath_common+0x50/0x68)
[ 59.790030] [<c0015430>] (warn_slowpath_common+0x50/0x68) from [<c00154dc>] (warn_slowpath_fmt+0x30/0x40)
[ 59.972322] [<c00154dc>] (warn_slowpath_fmt+0x30/0x40) from [<c000dc18>] (arm_dma_free+0x88/0xe4)
[ 60.070701] [<c000dc18>] (arm_dma_free+0x88/0xe4) from [<c008fa30>] (dma_pool_destroy+0x100/0x148)
[ 60.256817] [<c008fa30>] (dma_pool_destroy+0x100/0x148) from [<c019a64c>] (release_nodes+0x144/0x218)
[ 60.445201] [<c019a64c>] (release_nodes+0x144/0x218) from [<c0197e10>] (__device_release_driver+0x60/0xb8)
[ 60.634148] [<c0197e10>] (__device_release_driver+0x60/0xb8) from [<c0198608>] (driver_detach+0xd8/0xec)
[ 60.823623] [<c0198608>] (driver_detach+0xd8/0xec) from [<c0197c54>] (bus_remove_driver+0x7c/0xc4)
[ 61.013268] [<c0197c54>] (bus_remove_driver+0x7c/0xc4) from [<c004bfac>] (sys_delete_module+0x19c/0x220)
[ 61.203472] [<c004bfac>] (sys_delete_module+0x19c/0x220) from [<c0009140>] (ret_fast_syscall+0x0/0x2c)
[ 61.393390] ---[ end trace 0745420412c0325b ]---

The patch fixes this.

Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
---
arch/arm/mm/dma-mapping.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index c2cdf65..2cc77b7 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -648,12 +648,12 @@ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,

if (arch_is_coherent() || nommu()) {
__dma_free_buffer(page, size);
+ } else if (__free_from_pool(cpu_addr, size)) {
+ return;
} else if (!IS_ENABLED(CONFIG_CMA)) {
__dma_free_remap(cpu_addr, size);
__dma_free_buffer(page, size);
} else {
- if (__free_from_pool(cpu_addr, size))
- return;
/*
* Non-atomic allocations cannot be freed with IRQs disabled
*/
--
1.7.2.5

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