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mmc: host: sdhci check parameters before call dma_free_coherent

PATCH Applied Peng Fan 3 participants 4 messages Jun 22, 2015 – Jul 20, 2015

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Peng Fan

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#0 lore raw

PATCH 1/1 mmc: host: sdhci check parameters before call dma_free_coherent

We should not call dma_free_coherent if host->adma_table is NULL, otherwise may trigger panic.

Quoted 1 line

From DMA-API.txt:

"
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)

Free a region of consistent memory you previously allocated. dev, size and dma_handle must all be the same as those passed into dma_alloc_coherent(). cpu_addr must be the virtual address returned by the dma_alloc_coherent().
"
So we should check cpu_addr, but not directly call dma_free_coherent.

I met this when porting xen, log: "
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = 80004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.38-02383-g5ccf32b-dirty #22
task: 84074000 ti: 84078000 task.ti: 84078000
PC is at bitmap_clear+0xc0/0xdc
LR is at bitmap_clear+0x54/0xdc
pc : [<8029deb8>]    lr : [<8029de4c>]    psr: 20000193

sp : 84079d80 ip : 00000001 fp : 00000000
r10: 00077fff r9 : 00000404 r8 : 00000001
r7 : 00000001 r6 : 00000001 r5 : 00000000 r4 : ffffffff r3 : 00000001 r2 : 00000001 r1 : 20000193 r0 : 00000015
Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c53c7d Table: 8800406a DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0x84078238)

Stack: (0x84079d80 to 0x8407a000)

9d80: 80000113 00000000 87efa000 81109918 00001000 800197f8 84128558 00080008 9da0: 84079dec 000000d0 84bfeac0 84126c10 84126c10 ffffffff 00000404 ffffffff 9dc0: 00000000 00000402 00000000 00000000 84126c10 80310ba8 ffffffff 00000000 9de0: 00000000 00000524 84078000 00000000 00000000 ffffffff ffffffff 84bfeac0 9e00: 84bfe800 8000b407 07eb0000 8116e0f8 00000000 804ee81c ffffffff ffffffff 9e20: 00000000 84126c10 84c92010 84bfeac0 00000000 84126c10 84126c00 84bfeac0 9e40: 84078030 804f08e4 804f03d8 84126c10 fffffdfb 8115401c 8115401c 00000000 9e60: 0000010f 80362330 803622ec 84126c10 811c8098 00000000 8115401c 80360b1c 9e80: 84126c10 8115401c 84126c44 00000000 80de1888 80360d28 00000000 8115401c 9ea0: 80360c9c 8035f10c 8406965c 84123634 8115401c 84c8bf80 8112f3c8 803602bc 9ec0: 80d08314 8115401c 00000006 8115401c 00000006 8116e080 8116e080 8036130c 9ee0: 00000000 80e00f78 00000006 800088dc 8400f900 80c94fe0 840bd480 80735184 9f00: 00000000 8116e080 0000150c 8012d430 00000000 811105b0 60000113 00000001 9f20: 87ffc576 8075ca38 0000010f 8004b0f0 80d66884 00000006 87ffc583 00000006 9f40: 811105a0 80e00f78 00000006 8116e080 8116e080 80da150c 0000010f 80df4154 9f60: 80df4148 80da1c4c 00000006 00000006 80da150c 9355553c 84079f9c 80731338 9f80: 00000000 00000000 80727254 00000000 00000000 00000000 00000000 00000000 9fa0: 00000000 8072725c 00000000 8000ecf8 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 9355553c 9355553c [<8029deb8>] (bitmap_clear) from [<800197f8>] (__arm_dma_free.isra.18+0xe4/0x228) [<800197f8>] (__arm_dma_free.isra.18) from [<80310ba8>] (xen_swiotlb_free_coherent+0xfc/0x140) [<80310ba8>] (xen_swiotlb_free_coherent) from [<804ee81c>] (sdhci_add_host+0xb34/0xe64) [<804ee81c>] (sdhci_add_host) from [<804f08e4>] (sdhci_esdhc_imx_probe+0x50c/0x808) [<804f08e4>] (sdhci_esdhc_imx_probe) from [<80362330>] (platform_drv_probe+0x44/0xa4) [<80362330>] (platform_drv_probe) from [<80360b1c>] (driver_probe_device+0x120/0x25c) [<80360b1c>] (driver_probe_device) from [<80360d28>] (__driver_attach+0x8c/0x90) [<80360d28>] (__driver_attach) from [<8035f10c>] (bus_for_each_dev+0x60/0x94) [<8035f10c>] (bus_for_each_dev) from [<803602bc>] (bus_add_driver+0x148/0x1f0) [<803602bc>] (bus_add_driver) from [<8036130c>] (driver_register+0x78/0xf8) [<8036130c>] (driver_register) from [<800088dc>] (do_one_initcall+0xf8/0x144) [<800088dc>] (do_one_initcall) from [<80da1c4c>] (kernel_init_freeable+0x138/0x1d8) [<80da1c4c>] (kernel_init_freeable) from [<8072725c>] (kernel_init+0x8/0xf0) [<8072725c>] (kernel_init) from [<8000ecf8>] (ret_from_fork+0x14/0x3c)

Code: 10866003 1206601f 10633006 11e02312 (e5953000)
---[ end trace f6f103bb73cc0503 ]---
note: swapper/0[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b"

Because dma_alloc_coherent fail, it returns NULL, then
"if (!host->adma_table || !host->align_buffer)" will return true, then dma_free_coherent trigger panic.

After applying this patch, no panic and all work well, kernel log:
"
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: Unable to allocate ADMA buffers. Falling back to standard DMA.
mmc0: no vqmmc regulator found
mmc0: SDHCI controller on 30b40000.usdhc [30b40000.usdhc] using DMA "

---
 drivers/mmc/host/sdhci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
drivers/mmc/host/sdhci.c +5 -2
index 706bb60..52e2327 100644
@@ -2978,8 +2978,11 @@ int sdhci_add_host(struct sdhci_host *host)
 						      GFP_KERNEL);
 		host->align_buffer = kmalloc(host->align_buffer_sz, GFP_KERNEL);
 		if (!host->adma_table || !host->align_buffer) {
-			dma_free_coherent(mmc_dev(mmc), host->adma_table_sz,
-					  host->adma_table, host->adma_addr);
+			if (host->adma_table)
+				dma_free_coherent(mmc_dev(mmc),
+						  host->adma_table_sz,
+						  host->adma_table,
+						  host->adma_addr);
 			kfree(host->align_buffer);
 			pr_warn("%s: Unable to allocate ADMA buffers - falling back to standard DMA\n",
 				mmc_hostname(mmc));
Signature · 4 lines
1.8.4

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maintainer Acked-by on v1 1/1
#1 lore raw
Quoted 91 lines · Peng Fan

We should not call dma_free_coherent if host->adma_table is NULL, otherwise may trigger panic.

Quoted 1 line

From DMA-API.txt:

"
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)

Free a region of consistent memory you previously allocated. dev, size and dma_handle must all be the same as those passed into dma_alloc_coherent(). cpu_addr must be the virtual address returned by the dma_alloc_coherent().
"
So we should check cpu_addr, but not directly call dma_free_coherent.

I met this when porting xen, log: "
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = 80004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.38-02383-g5ccf32b-dirty #22
task: 84074000 ti: 84078000 task.ti: 84078000
PC is at bitmap_clear+0xc0/0xdc
LR is at bitmap_clear+0x54/0xdc
pc : [<8029deb8>]    lr : [<8029de4c>]    psr: 20000193

sp : 84079d80 ip : 00000001 fp : 00000000
r10: 00077fff r9 : 00000404 r8 : 00000001
r7 : 00000001 r6 : 00000001 r5 : 00000000 r4 : ffffffff r3 : 00000001 r2 : 00000001 r1 : 20000193 r0 : 00000015
Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c53c7d Table: 8800406a DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0x84078238)

Stack: (0x84079d80 to 0x8407a000)

9d80: 80000113 00000000 87efa000 81109918 00001000 800197f8 84128558 00080008 9da0: 84079dec 000000d0 84bfeac0 84126c10 84126c10 ffffffff 00000404 ffffffff 9dc0: 00000000 00000402 00000000 00000000 84126c10 80310ba8 ffffffff 00000000 9de0: 00000000 00000524 84078000 00000000 00000000 ffffffff ffffffff 84bfeac0 9e00: 84bfe800 8000b407 07eb0000 8116e0f8 00000000 804ee81c ffffffff ffffffff 9e20: 00000000 84126c10 84c92010 84bfeac0 00000000 84126c10 84126c00 84bfeac0 9e40: 84078030 804f08e4 804f03d8 84126c10 fffffdfb 8115401c 8115401c 00000000 9e60: 0000010f 80362330 803622ec 84126c10 811c8098 00000000 8115401c 80360b1c 9e80: 84126c10 8115401c 84126c44 00000000 80de1888 80360d28 00000000 8115401c 9ea0: 80360c9c 8035f10c 8406965c 84123634 8115401c 84c8bf80 8112f3c8 803602bc 9ec0: 80d08314 8115401c 00000006 8115401c 00000006 8116e080 8116e080 8036130c 9ee0: 00000000 80e00f78 00000006 800088dc 8400f900 80c94fe0 840bd480 80735184 9f00: 00000000 8116e080 0000150c 8012d430 00000000 811105b0 60000113 00000001 9f20: 87ffc576 8075ca38 0000010f 8004b0f0 80d66884 00000006 87ffc583 00000006 9f40: 811105a0 80e00f78 00000006 8116e080 8116e080 80da150c 0000010f 80df4154 9f60: 80df4148 80da1c4c 00000006 00000006 80da150c 9355553c 84079f9c 80731338 9f80: 00000000 00000000 80727254 00000000 00000000 00000000 00000000 00000000 9fa0: 00000000 8072725c 00000000 8000ecf8 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 9355553c 9355553c [<8029deb8>] (bitmap_clear) from [<800197f8>] (__arm_dma_free.isra.18+0xe4/0x228) [<800197f8>] (__arm_dma_free.isra.18) from [<80310ba8>] (xen_swiotlb_free_coherent+0xfc/0x140) [<80310ba8>] (xen_swiotlb_free_coherent) from [<804ee81c>] (sdhci_add_host+0xb34/0xe64) [<804ee81c>] (sdhci_add_host) from [<804f08e4>] (sdhci_esdhc_imx_probe+0x50c/0x808) [<804f08e4>] (sdhci_esdhc_imx_probe) from [<80362330>] (platform_drv_probe+0x44/0xa4) [<80362330>] (platform_drv_probe) from [<80360b1c>] (driver_probe_device+0x120/0x25c) [<80360b1c>] (driver_probe_device) from [<80360d28>] (__driver_attach+0x8c/0x90) [<80360d28>] (__driver_attach) from [<8035f10c>] (bus_for_each_dev+0x60/0x94) [<8035f10c>] (bus_for_each_dev) from [<803602bc>] (bus_add_driver+0x148/0x1f0) [<803602bc>] (bus_add_driver) from [<8036130c>] (driver_register+0x78/0xf8) [<8036130c>] (driver_register) from [<800088dc>] (do_one_initcall+0xf8/0x144) [<800088dc>] (do_one_initcall) from [<80da1c4c>] (kernel_init_freeable+0x138/0x1d8) [<80da1c4c>] (kernel_init_freeable) from [<8072725c>] (kernel_init+0x8/0xf0) [<8072725c>] (kernel_init) from [<8000ecf8>] (ret_from_fork+0x14/0x3c)

Code: 10866003 1206601f 10633006 11e02312 (e5953000)
---[ end trace f6f103bb73cc0503 ]---
note: swapper/0[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b"

Because dma_alloc_coherent fail, it returns NULL, then
"if (!host->adma_table || !host->align_buffer)" will return true, then dma_free_coherent trigger panic.

After applying this patch, no panic and all work well, kernel log:
"
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: Unable to allocate ADMA buffers. Falling back to standard DMA.
mmc0: no vqmmc regulator found
mmc0: SDHCI controller on 30b40000.usdhc [30b40000.usdhc] using DMA "

Quoted 1 line

Looks like the problem started in v3.16 with:

commit d1e49f77d7c7b75fdc022e1d46c1549bbc91c5b7

Author: Russell King <[email protected]>
Date:   Fri Apr 25 12:58:34 2014 +0100

mmc: sdhci: convert ADMA descriptors to a coherent allocation

Quoted 13 lines
---
 drivers/mmc/host/sdhci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
drivers/mmc/host/sdhci.c +0 -0
index 706bb60..52e2327 100644
@@ -2978,8 +2978,11 @@ int sdhci_add_host(struct sdhci_host *host)
 						      GFP_KERNEL);
 		host->align_buffer = kmalloc(host->align_buffer_sz, GFP_KERNEL);
 		if (!host->adma_table || !host->align_buffer) {

drivers/mmc/host/sdhci.c int sdhci_add_host(struct sdhci_host *host) · line 2988

Quoted 10 lines
drivers/mmc/host/sdhci.c +5 -2
-			dma_free_coherent(mmc_dev(mmc), host->adma_table_sz,
-					  host->adma_table, host->adma_addr);
+			if (host->adma_table)
+				dma_free_coherent(mmc_dev(mmc),
+						  host->adma_table_sz,
+						  host->adma_table,
+						  host->adma_addr);
 			kfree(host->align_buffer);
 			pr_warn("%s: Unable to allocate ADMA buffers - falling back to standard DMA\n",
 				mmc_hostname(mmc));

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author
#2 lore raw

Hi,

Quoted 96 lines · Adrian Hunter
Quoted 91 lines · Peng Fan

We should not call dma_free_coherent if host->adma_table is NULL, otherwise may trigger panic.

Quoted 1 line

From DMA-API.txt:

"
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)

Free a region of consistent memory you previously allocated. dev, size and dma_handle must all be the same as those passed into dma_alloc_coherent(). cpu_addr must be the virtual address returned by the dma_alloc_coherent().
"
So we should check cpu_addr, but not directly call dma_free_coherent.

I met this when porting xen, log: "
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = 80004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.38-02383-g5ccf32b-dirty #22
task: 84074000 ti: 84078000 task.ti: 84078000
PC is at bitmap_clear+0xc0/0xdc
LR is at bitmap_clear+0x54/0xdc
pc : [<8029deb8>]    lr : [<8029de4c>]    psr: 20000193

sp : 84079d80 ip : 00000001 fp : 00000000
r10: 00077fff r9 : 00000404 r8 : 00000001
r7 : 00000001 r6 : 00000001 r5 : 00000000 r4 : ffffffff r3 : 00000001 r2 : 00000001 r1 : 20000193 r0 : 00000015
Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c53c7d Table: 8800406a DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0x84078238)

Stack: (0x84079d80 to 0x8407a000)

9d80: 80000113 00000000 87efa000 81109918 00001000 800197f8 84128558 00080008 9da0: 84079dec 000000d0 84bfeac0 84126c10 84126c10 ffffffff 00000404 ffffffff 9dc0: 00000000 00000402 00000000 00000000 84126c10 80310ba8 ffffffff 00000000 9de0: 00000000 00000524 84078000 00000000 00000000 ffffffff ffffffff 84bfeac0 9e00: 84bfe800 8000b407 07eb0000 8116e0f8 00000000 804ee81c ffffffff ffffffff 9e20: 00000000 84126c10 84c92010 84bfeac0 00000000 84126c10 84126c00 84bfeac0 9e40: 84078030 804f08e4 804f03d8 84126c10 fffffdfb 8115401c 8115401c 00000000 9e60: 0000010f 80362330 803622ec 84126c10 811c8098 00000000 8115401c 80360b1c 9e80: 84126c10 8115401c 84126c44 00000000 80de1888 80360d28 00000000 8115401c 9ea0: 80360c9c 8035f10c 8406965c 84123634 8115401c 84c8bf80 8112f3c8 803602bc 9ec0: 80d08314 8115401c 00000006 8115401c 00000006 8116e080 8116e080 8036130c 9ee0: 00000000 80e00f78 00000006 800088dc 8400f900 80c94fe0 840bd480 80735184 9f00: 00000000 8116e080 0000150c 8012d430 00000000 811105b0 60000113 00000001 9f20: 87ffc576 8075ca38 0000010f 8004b0f0 80d66884 00000006 87ffc583 00000006 9f40: 811105a0 80e00f78 00000006 8116e080 8116e080 80da150c 0000010f 80df4154 9f60: 80df4148 80da1c4c 00000006 00000006 80da150c 9355553c 84079f9c 80731338 9f80: 00000000 00000000 80727254 00000000 00000000 00000000 00000000 00000000 9fa0: 00000000 8072725c 00000000 8000ecf8 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 9355553c 9355553c [<8029deb8>] (bitmap_clear) from [<800197f8>] (__arm_dma_free.isra.18+0xe4/0x228) [<800197f8>] (__arm_dma_free.isra.18) from [<80310ba8>] (xen_swiotlb_free_coherent+0xfc/0x140) [<80310ba8>] (xen_swiotlb_free_coherent) from [<804ee81c>] (sdhci_add_host+0xb34/0xe64) [<804ee81c>] (sdhci_add_host) from [<804f08e4>] (sdhci_esdhc_imx_probe+0x50c/0x808) [<804f08e4>] (sdhci_esdhc_imx_probe) from [<80362330>] (platform_drv_probe+0x44/0xa4) [<80362330>] (platform_drv_probe) from [<80360b1c>] (driver_probe_device+0x120/0x25c) [<80360b1c>] (driver_probe_device) from [<80360d28>] (__driver_attach+0x8c/0x90) [<80360d28>] (__driver_attach) from [<8035f10c>] (bus_for_each_dev+0x60/0x94) [<8035f10c>] (bus_for_each_dev) from [<803602bc>] (bus_add_driver+0x148/0x1f0) [<803602bc>] (bus_add_driver) from [<8036130c>] (driver_register+0x78/0xf8) [<8036130c>] (driver_register) from [<800088dc>] (do_one_initcall+0xf8/0x144) [<800088dc>] (do_one_initcall) from [<80da1c4c>] (kernel_init_freeable+0x138/0x1d8) [<80da1c4c>] (kernel_init_freeable) from [<8072725c>] (kernel_init+0x8/0xf0) [<8072725c>] (kernel_init) from [<8000ecf8>] (ret_from_fork+0x14/0x3c)

Code: 10866003 1206601f 10633006 11e02312 (e5953000)
---[ end trace f6f103bb73cc0503 ]---
note: swapper/0[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b"

Because dma_alloc_coherent fail, it returns NULL, then
"if (!host->adma_table || !host->align_buffer)" will return true, then dma_free_coherent trigger panic.

After applying this patch, no panic and all work well, kernel log:
"
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: Unable to allocate ADMA buffers. Falling back to standard DMA.
mmc0: no vqmmc regulator found
mmc0: SDHCI controller on 30b40000.usdhc [30b40000.usdhc] using DMA "

Quoted 1 line
Quoted 8 lines

Looks like the problem started in v3.16 with:

commit d1e49f77d7c7b75fdc022e1d46c1549bbc91c5b7

Author: Russell King <[email protected]>
Date:   Fri Apr 25 12:58:34 2014 +0100

mmc: sdhci: convert ADMA descriptors to a coherent allocation

Will this patch be merged? Since more than 3 weeks passed, I did not see any further comments about this patch.

Quoted 17 lines
Quoted 17 lines

---
 drivers/mmc/host/sdhci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
drivers/mmc/host/sdhci.c +1 -2
index 706bb60..52e2327 100644
@@ -2978,8 +2978,11 @@ int sdhci_add_host(struct sdhci_host *host)
 						      GFP_KERNEL);
 		host->align_buffer = kmalloc(host->align_buffer_sz, GFP_KERNEL);
 		if (!host->adma_table || !host->align_buffer) {
-			dma_free_coherent(mmc_dev(mmc), host->adma_table_sz,
-					  host->adma_table, host->adma_addr);
+			if (host->adma_table)
Quoted 9 lines

drivers/mmc/host/sdhci.c int sdhci_add_host(struct sdhci_host *host) · line 2988

Quoted 8 lines
drivers/mmc/host/sdhci.c +4 -0
+				dma_free_coherent(mmc_dev(mmc),
+						  host->adma_table_sz,
+						  host->adma_table,
+						  host->adma_addr);
 			kfree(host->align_buffer);
 			pr_warn("%s: Unable to allocate ADMA buffers - falling back to standard DMA\n",
 				mmc_hostname(mmc));

Thanks,
Peng

Applied
#3 lore raw
In reply to Adrian Hunter
Quoted 96 lines · Adrian Hunter
Quoted 91 lines · Peng Fan

We should not call dma_free_coherent if host->adma_table is NULL, otherwise may trigger panic.

Quoted 1 line

From DMA-API.txt:

"
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)

Free a region of consistent memory you previously allocated. dev, size and dma_handle must all be the same as those passed into dma_alloc_coherent(). cpu_addr must be the virtual address returned by the dma_alloc_coherent().
"
So we should check cpu_addr, but not directly call dma_free_coherent.

I met this when porting xen, log: "
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = 80004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.38-02383-g5ccf32b-dirty #22
task: 84074000 ti: 84078000 task.ti: 84078000
PC is at bitmap_clear+0xc0/0xdc
LR is at bitmap_clear+0x54/0xdc
pc : [<8029deb8>]    lr : [<8029de4c>]    psr: 20000193

sp : 84079d80 ip : 00000001 fp : 00000000
r10: 00077fff r9 : 00000404 r8 : 00000001
r7 : 00000001 r6 : 00000001 r5 : 00000000 r4 : ffffffff r3 : 00000001 r2 : 00000001 r1 : 20000193 r0 : 00000015
Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c53c7d Table: 8800406a DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0x84078238)

Stack: (0x84079d80 to 0x8407a000)

9d80: 80000113 00000000 87efa000 81109918 00001000 800197f8 84128558 00080008 9da0: 84079dec 000000d0 84bfeac0 84126c10 84126c10 ffffffff 00000404 ffffffff 9dc0: 00000000 00000402 00000000 00000000 84126c10 80310ba8 ffffffff 00000000 9de0: 00000000 00000524 84078000 00000000 00000000 ffffffff ffffffff 84bfeac0 9e00: 84bfe800 8000b407 07eb0000 8116e0f8 00000000 804ee81c ffffffff ffffffff 9e20: 00000000 84126c10 84c92010 84bfeac0 00000000 84126c10 84126c00 84bfeac0 9e40: 84078030 804f08e4 804f03d8 84126c10 fffffdfb 8115401c 8115401c 00000000 9e60: 0000010f 80362330 803622ec 84126c10 811c8098 00000000 8115401c 80360b1c 9e80: 84126c10 8115401c 84126c44 00000000 80de1888 80360d28 00000000 8115401c 9ea0: 80360c9c 8035f10c 8406965c 84123634 8115401c 84c8bf80 8112f3c8 803602bc 9ec0: 80d08314 8115401c 00000006 8115401c 00000006 8116e080 8116e080 8036130c 9ee0: 00000000 80e00f78 00000006 800088dc 8400f900 80c94fe0 840bd480 80735184 9f00: 00000000 8116e080 0000150c 8012d430 00000000 811105b0 60000113 00000001 9f20: 87ffc576 8075ca38 0000010f 8004b0f0 80d66884 00000006 87ffc583 00000006 9f40: 811105a0 80e00f78 00000006 8116e080 8116e080 80da150c 0000010f 80df4154 9f60: 80df4148 80da1c4c 00000006 00000006 80da150c 9355553c 84079f9c 80731338 9f80: 00000000 00000000 80727254 00000000 00000000 00000000 00000000 00000000 9fa0: 00000000 8072725c 00000000 8000ecf8 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 9355553c 9355553c [<8029deb8>] (bitmap_clear) from [<800197f8>] (__arm_dma_free.isra.18+0xe4/0x228) [<800197f8>] (__arm_dma_free.isra.18) from [<80310ba8>] (xen_swiotlb_free_coherent+0xfc/0x140) [<80310ba8>] (xen_swiotlb_free_coherent) from [<804ee81c>] (sdhci_add_host+0xb34/0xe64) [<804ee81c>] (sdhci_add_host) from [<804f08e4>] (sdhci_esdhc_imx_probe+0x50c/0x808) [<804f08e4>] (sdhci_esdhc_imx_probe) from [<80362330>] (platform_drv_probe+0x44/0xa4) [<80362330>] (platform_drv_probe) from [<80360b1c>] (driver_probe_device+0x120/0x25c) [<80360b1c>] (driver_probe_device) from [<80360d28>] (__driver_attach+0x8c/0x90) [<80360d28>] (__driver_attach) from [<8035f10c>] (bus_for_each_dev+0x60/0x94) [<8035f10c>] (bus_for_each_dev) from [<803602bc>] (bus_add_driver+0x148/0x1f0) [<803602bc>] (bus_add_driver) from [<8036130c>] (driver_register+0x78/0xf8) [<8036130c>] (driver_register) from [<800088dc>] (do_one_initcall+0xf8/0x144) [<800088dc>] (do_one_initcall) from [<80da1c4c>] (kernel_init_freeable+0x138/0x1d8) [<80da1c4c>] (kernel_init_freeable) from [<8072725c>] (kernel_init+0x8/0xf0) [<8072725c>] (kernel_init) from [<8000ecf8>] (ret_from_fork+0x14/0x3c)

Code: 10866003 1206601f 10633006 11e02312 (e5953000)
---[ end trace f6f103bb73cc0503 ]---
note: swapper/0[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b"

Because dma_alloc_coherent fail, it returns NULL, then
"if (!host->adma_table || !host->align_buffer)" will return true, then dma_free_coherent trigger panic.

After applying this patch, no panic and all work well, kernel log:
"
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: Unable to allocate ADMA buffers. Falling back to standard DMA.
mmc0: no vqmmc regulator found
mmc0: SDHCI controller on 30b40000.usdhc [30b40000.usdhc] using DMA "

Quoted 1 line
Quoted 9 lines

Looks like the problem started in v3.16 with:

commit d1e49f77d7c7b75fdc022e1d46c1549bbc91c5b7

Author: Russell King <[email protected]>
Date:   Fri Apr 25 12:58:34 2014 +0100

mmc: sdhci: convert ADMA descriptors to a coherent allocation

Thanks, applied for fixes. I cleaned up the change log, I think it was a bit too verbose and I also added above fixes tag which was pointed out by Adrian.

Sorry for the delay!

Kind regards
Uffe