mtd: spi-nor: core: Prevent oops during driver removal with active read or write operations

PATCH In review Khairul Anuar Romli 2 participants 6 messages Jul 30, 2025 – Aug 21, 2025 1 message not in the archive

Subsystems (2)

Memory technology devices (MTD) SPI NOR

lore

Share & tools

lore

A message that is not in the archive (sent off-list or not yet received): [email protected]

Khairul Anuar Romli

author

2025-07-30 01:39 UTC #1 lore raw

PATCH v3 1/1 mtd: spi-nor: core: Prevent oops during driver removal with active read or write operations

From: kromli <[email protected]>

Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:

[  200.448732] Unable to handle kernel NULL pointer deref
erence at virtual address 0000000000000010
[  200.457576] Mem abort info:
[  200.460370]   ESR = 0x0000000096000004
[  200.464136]   EC = 0x25: DABT (current EL), IL = 32 bits
[  200.469527]   SET = 0, FnV = 0
[  200.472609]   EA = 0, S1PTW = 0
[  200.475904]   FSC = 0x04: level 0 translation fault
[  200.480786] Data abort info:
[  200.483659]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  200.489141]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  200.494189]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  200.499500] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000185df8000
[  200.505932] [0000000000000010] pgd=0000000000000000, p4d=0000000000000000
[  200.512720] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[  200.518968] Modules linked in: 8021q garp mrp stp llc bluetooth ecdh_generic
ecc rfkill crct10dif_ce rtc_ds1307 at24 stratix10_soc soc64_hwmon gpio_altera of
_fpga_region fpga_region fpga_bridge uio_pdrv_genirq uio fuse drm backlight ipv6
[  200.540016] CPU: 0 UID: 0 PID: 372 Comm: dd Not tainted 6.12.19-altera-gb6b26
c4179a6 #1
[  200.547996] Hardware name: SoCFPGA Stratix 10 SoCDK (DT)
[  200.553292] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  200.560234] pc : spi_nor_put_device+0x30/0x60
[  200.564594] lr : __put_mtd_device+0x8c/0x120
[  200.568856] sp : ffff80008411bc20
[  200.572161] x29: ffff80008411bc20 x28: ffff000185e2c500 x27: 0000000000000000
[  200.579282] x26: 0000000000000000 x25: ffff000185e2cb00 x24: ffff000185e2cc88
[  200.586404] x23: ffff00018034c620 x22: 0000000000000001 x21: ffff00018873e080
[  200.593524] x20: 0000000000000000 x19: ffff00018873e080 x18: ffffffffffffffff
[  200.600645] x17: 0030393d524f4a41 x16: 4d0064746d3d4d45 x15: ffff000185757700
[  200.607767] x14: 0000000000000000 x13: ffff000180045010 x12: ffff0001857576c0
[  200.614888] x11: 000000000000003a x10: ffff000180045018 x9 : ffff000180045010
[  200.622009] x8 : ffff80008411bb70 x7 : 0000000000000000 x6 : ffff000181325048
[  200.629129] x5 : 00000000820001cf x4 : fffffdffc60095e0 x3 : 0000000000000000
[  200.636250] x2 : 0000000000000000 x1 : ffff00018873e080 x0 : 0000000000000000
[  200.643371] Call trace:
[  200.645811]  spi_nor_put_device+0x30/0x60
[  200.649816]  __put_mtd_device+0x8c/0x120
[  200.653731]  put_mtd_device+0x30/0x48
[  200.657387]  mtdchar_close+0x30/0x78
[  200.660958]  __fput+0xc8/0x2d0
[  200.664011]  ____fput+0x14/0x20
[  200.667146]  task_work_run+0x70/0xdc
[  200.670718]  do_exit+0x2b4/0x8e4
[  200.673944]  do_group_exit+0x34/0x90
[  200.677512]  pid_child_should_wake+0x0/0x60
[  200.681686]  invoke_syscall+0x48/0x104
[  200.685432]  el0_svc_common.constprop.0+0xc0/0xe0
[  200.690128]  do_el0_svc+0x1c/0x28
[  200.693439]  el0_svc+0x30/0xcc
[  200.696454] dw_mmc ff808000.mmc: Unexpected interrupt latency
[  200.696485]  el0t_64_sync_handler+0x120/0x12c
[  200.706552]  el0t_64_sync+0x190/0x194
[  200.710213] Code: f9400000 f9417c00 f9402000 f9403400 (f9400800)
[  200.716290] ---[ end trace 0000000000000000 ]---
[  200.720948] Fixing recursive fault but reboot is needed!

Fixes be94215be1ab ("mtd: spi-nor: core: Fix an issue of releasing resources during read/write")

CC [email protected] # 6.12+

Signed-off-by Khairul Anuar Romli <[email protected]>

Reviewed-by Matthew Gerlach <[email protected]>

---
Changes in v3:
- exclude !dev && !dev->driver check in spi_nor_get_device to resolve kernel test robot smatchwarnings.
Changes in v2:
- Move the null check prior to try_module_get().

---
 drivers/mtd/spi-nor/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

drivers/mtd/spi-nor/core.c +5 -1

index ac4b960101cc..eb21d660036b 100644
@@ -3210,6 +3210,9 @@ static int spi_nor_get_device(struct mtd_info *mtd)
 	else
 		dev = nor->dev;
 
+	if (!dev->driver->owner)
+		return -EINVAL;
+
 	if (!try_module_get(dev->driver->owner))
 		return -ENODEV;

@@ -3227,7 +3230,8 @@ static void spi_nor_put_device(struct mtd_info *mtd)
 	else
 		dev = nor->dev;
 
-	module_put(dev->driver->owner);
+	if (dev && dev->driver && dev->driver->owner)
+		module_put(dev->driver->owner);
 }
 
 static void spi_nor_restore(struct spi_nor *nor)

Signature · 1 line

2.35.3

Michael Walle

maintainer

2025-07-30 07:30 UTC #2 lore raw

Hi,

Quoted 6 lines · Khairul Anuar Romli

From: kromli <[email protected]>
Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:

As already asked in v2. This needs a (more detailed) description what is going on and what is going wrong.

-michael

Quoted 95 lines

[  200.448732] Unable to handle kernel NULL pointer deref
erence at virtual address 0000000000000010
[  200.457576] Mem abort info:
[  200.460370]   ESR = 0x0000000096000004
[  200.464136]   EC = 0x25: DABT (current EL), IL = 32 bits
[  200.469527]   SET = 0, FnV = 0
[  200.472609]   EA = 0, S1PTW = 0
[  200.475904]   FSC = 0x04: level 0 translation fault
[  200.480786] Data abort info:
[  200.483659]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  200.489141]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  200.494189]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  200.499500] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000185df8000
[  200.505932] [0000000000000010] pgd=0000000000000000, p4d=0000000000000000
[  200.512720] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[  200.518968] Modules linked in: 8021q garp mrp stp llc bluetooth ecdh_generic
ecc rfkill crct10dif_ce rtc_ds1307 at24 stratix10_soc soc64_hwmon gpio_altera of
_fpga_region fpga_region fpga_bridge uio_pdrv_genirq uio fuse drm backlight ipv6
[  200.540016] CPU: 0 UID: 0 PID: 372 Comm: dd Not tainted 6.12.19-altera-gb6b26
c4179a6 #1
[  200.547996] Hardware name: SoCFPGA Stratix 10 SoCDK (DT)
[  200.553292] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  200.560234] pc : spi_nor_put_device+0x30/0x60
[  200.564594] lr : __put_mtd_device+0x8c/0x120
[  200.568856] sp : ffff80008411bc20
[  200.572161] x29: ffff80008411bc20 x28: ffff000185e2c500 x27: 0000000000000000
[  200.579282] x26: 0000000000000000 x25: ffff000185e2cb00 x24: ffff000185e2cc88
[  200.586404] x23: ffff00018034c620 x22: 0000000000000001 x21: ffff00018873e080
[  200.593524] x20: 0000000000000000 x19: ffff00018873e080 x18: ffffffffffffffff
[  200.600645] x17: 0030393d524f4a41 x16: 4d0064746d3d4d45 x15: ffff000185757700
[  200.607767] x14: 0000000000000000 x13: ffff000180045010 x12: ffff0001857576c0
[  200.614888] x11: 000000000000003a x10: ffff000180045018 x9 : ffff000180045010
[  200.622009] x8 : ffff80008411bb70 x7 : 0000000000000000 x6 : ffff000181325048
[  200.629129] x5 : 00000000820001cf x4 : fffffdffc60095e0 x3 : 0000000000000000
[  200.636250] x2 : 0000000000000000 x1 : ffff00018873e080 x0 : 0000000000000000
[  200.643371] Call trace:
[  200.645811]  spi_nor_put_device+0x30/0x60
[  200.649816]  __put_mtd_device+0x8c/0x120
[  200.653731]  put_mtd_device+0x30/0x48
[  200.657387]  mtdchar_close+0x30/0x78
[  200.660958]  __fput+0xc8/0x2d0
[  200.664011]  ____fput+0x14/0x20
[  200.667146]  task_work_run+0x70/0xdc
[  200.670718]  do_exit+0x2b4/0x8e4
[  200.673944]  do_group_exit+0x34/0x90
[  200.677512]  pid_child_should_wake+0x0/0x60
[  200.681686]  invoke_syscall+0x48/0x104
[  200.685432]  el0_svc_common.constprop.0+0xc0/0xe0
[  200.690128]  do_el0_svc+0x1c/0x28
[  200.693439]  el0_svc+0x30/0xcc
[  200.696454] dw_mmc ff808000.mmc: Unexpected interrupt latency
[  200.696485]  el0t_64_sync_handler+0x120/0x12c
[  200.706552]  el0t_64_sync+0x190/0x194
[  200.710213] Code: f9400000 f9417c00 f9402000 f9403400 (f9400800)
[  200.716290] ---[ end trace 0000000000000000 ]---
[  200.720948] Fixing recursive fault but reboot is needed!

Fixes be94215be1ab ("mtd: spi-nor: core: Fix an issue of releasing resources during read/write")

CC [email protected] # 6.12+

Signed-off-by Khairul Anuar Romli <[email protected]>

Reviewed-by Matthew Gerlach <[email protected]>

---
Changes in v3:
- exclude !dev && !dev->driver check in spi_nor_get_device to resolve kernel test robot smatchwarnings.
Changes in v2:
- Move the null check prior to try_module_get().

---
 drivers/mtd/spi-nor/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

drivers/mtd/spi-nor/core.c +5 -1

index ac4b960101cc..eb21d660036b 100644
@@ -3210,6 +3210,9 @@ static int spi_nor_get_device(struct mtd_info *mtd)
 	else
 		dev = nor->dev;
 
+	if (!dev->driver->owner)
+		return -EINVAL;
+
 	if (!try_module_get(dev->driver->owner))
 		return -ENODEV;

@@ -3227,7 +3230,8 @@ static void spi_nor_put_device(struct mtd_info *mtd)
 	else
 		dev = nor->dev;
 
-	module_put(dev->driver->owner);
+	if (dev && dev->driver && dev->driver->owner)
+		module_put(dev->driver->owner);
 }
 
 static void spi_nor_restore(struct spi_nor *nor)

Romli, Khairul Anuar

author

2025-07-30 07:46 UTC #3 lore raw

Quoted 24 lines

-----Original Message-----
From: Michael Walle <[email protected]>
Sent: Wednesday, 30 July, 2025 3:30 PM
To: Romli, Khairul Anuar <[email protected]>; Tudor Ambarus <[email protected]>; Pratyush Yadav <[email protected]>; Miquel Raynal <[email protected]>; Richard Weinberger <[email protected]>; Vignesh Raghavendra <[email protected]>; open list:SPI NOR SUBSYSTEM <[email protected]>; open list <[email protected]>; Gerlach, Matthew <[email protected]>
Subject: Re: [PATCH v3 1/1] mtd: spi-nor: core: Prevent oops during driver removal with active read or write operations
Hi,
Quoted 6 lines · Khairul Anuar Romli
From: kromli <[email protected]>
Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:

Quoted 4 lines

As already asked in v2. This needs a (more detailed) description what is going on and what is going wrong.
-michael

Hi,

We just run the following test we observe the crash.

time dd if=/dev/mtd1 of=out.img bs=1MB count=1000 & echo spi0.0 > /sys/bus/spi/drivers/spi-nor/unbind echo spi0.0 > /sys/bus/spi/drivers/spi-nor/bind

From the observation, the dd is not entirely terminated when the unbind took place. Maybe there is other changes require to ensure the dd operation gets terminated when driver unbind/remove.

Quoted 102 lines

Quoted 12 lines
[  200.448732] Unable to handle kernel NULL pointer deref erence at
virtual address 0000000000000010 [  200.457576] Mem abort info:
[  200.460370]   ESR = 0x0000000096000004
[  200.464136]   EC = 0x25: DABT (current EL), IL = 32 bits
[  200.469527]   SET = 0, FnV = 0
[  200.472609]   EA = 0, S1PTW = 0
[  200.475904]   FSC = 0x04: level 0 translation fault
[  200.480786] Data abort info:
[  200.483659]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  200.489141]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  200.494189]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  200.499500] user pgtable: 4k pages, 48-bit VAs,
Quoted 2 lines
pgdp=0000000185df8000 [ 200.505932] [0000000000000010] pgd=0000000000000000, p4d=0000000000000000 [ 200.512720]
Internal
Quoted 1 line
error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 200.518968]
Modules
Quoted 7 lines
linked in: 8021q garp mrp stp llc bluetooth ecdh_generic ecc rfkill crct10dif_ce rtc_ds1307 at24 stratix10_soc soc64_hwmon gpio_altera of _fpga_region fpga_region fpga_bridge uio_pdrv_genirq uio fuse drm backlight ipv6 [ 200.540016] CPU: 0 UID: 0 PID: 372 Comm: dd Not tainted 6.12.19-altera-gb6b26
c4179a6 #1
[  200.547996] Hardware name: SoCFPGA Stratix 10 SoCDK (DT) [
Quoted 15 lines
200.553292] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 200.560234] pc : spi_nor_put_device+0x30/0x60 [ 200.564594] lr : __put_mtd_device+0x8c/0x120 [ 200.568856] sp :
ffff80008411bc20 [ 200.572161] x29: ffff80008411bc20 x28:
ffff000185e2c500 x27: 0000000000000000 [ 200.579282] x26:
0000000000000000 x25: ffff000185e2cb00 x24: ffff000185e2cc88 [ 200.586404] x23: ffff00018034c620 x22: 0000000000000001 x21:
ffff00018873e080 [ 200.593524] x20: 0000000000000000 x19:
ffff00018873e080 x18: ffffffffffffffff [ 200.600645] x17:
0030393d524f4a41 x16: 4d0064746d3d4d45 x15: ffff000185757700 [ 200.607767] x14: 0000000000000000 x13: ffff000180045010 x12:
ffff0001857576c0 [ 200.614888] x11: 000000000000003a x10:
ffff000180045018 x9 : ffff000180045010 [ 200.622009] x8 :
ffff80008411bb70 x7 : 0000000000000000 x6 : ffff000181325048 [ 200.629129] x5 : 00000000820001cf x4 : fffffdffc60095e0 x3 :
0000000000000000 [ 200.636250] x2 : 0000000000000000 x1 :
ffff00018873e080 x0 : 0000000000000000 [ 200.643371] Call trace:
Quoted 2 lines
[  200.645811]  spi_nor_put_device+0x30/0x60 [  200.649816]
__put_mtd_device+0x8c/0x120 [ 200.653731]
put_mtd_device+0x30/0x48 [
> 200.657387]  mtdchar_close+0x30/0x78 [  200.660958]
__fput+0xc8/0x2d0
> [  200.664011]  ____fput+0x14/0x20 [  200.667146]
> task_work_run+0x70/0xdc [  200.670718]  do_exit+0x2b4/0x8e4 [
> 200.673944]  do_group_exit+0x34/0x90 [  200.677512]
> pid_child_should_wake+0x0/0x60 [  200.681686]
> invoke_syscall+0x48/0x104 [  200.685432]
> el0_svc_common.constprop.0+0xc0/0xe0
> [  200.690128]  do_el0_svc+0x1c/0x28
> [  200.693439]  el0_svc+0x30/0xcc
drivers/mtd/spi-nor/core.c static int spi_nor_get_device(struct mtd_info
Quoted 27 lines
[  200.696454] dw_mmc ff808000.mmc: Unexpected interrupt latency [
200.696485] el0t_64_sync_handler+0x120/0x12c [ 200.706552] el0t_64_sync+0x190/0x194 [ 200.710213] Code: f9400000 f9417c00 f9402000 f9403400 (f9400800) [ 200.716290] ---[ end trace 0000000000000000 ]--- [ 200.720948] Fixing recursive fault but reboot is needed!
Fixes be94215be1ab ("mtd: spi-nor: core: Fix an issue of releasing
resources during read/write")
CC [email protected] # 6.12+
Signed-off-by Khairul Anuar Romli <[email protected]>
Reviewed-by Matthew Gerlach <[email protected]>
---
Changes in v3:
- exclude !dev && !dev->driver check in spi_nor_get_device to resolve kernel test robot smatchwarnings.
Changes in v2:
- Move the null check prior to try_module_get().
---
 drivers/mtd/spi-nor/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/mtd/spi-nor/core.c +0 -0
index ac4b960101cc..eb21d660036b 100644
@@ -3210,6 +3210,9 @@ static int spi_nor_get_device(struct mtd_info
*mtd)
drivers/mtd/spi-nor/core.c static void spi_nor_put_device(struct mtd_info
Quoted 10 lines
drivers/mtd/spi-nor/core.c +3 -0
 	else
 		dev = nor->dev;
 
+	if (!dev->driver->owner)
+		return -EINVAL;
+
 	if (!try_module_get(dev->driver->owner))
 		return -ENODEV;
 
@@ -3227,7 +3230,8 @@ static void spi_nor_put_device(struct mtd_info
*mtd)
Quoted 9 lines
drivers/mtd/spi-nor/core.c +2 -1
 	else
 		dev = nor->dev;
 
-	module_put(dev->driver->owner);
+	if (dev && dev->driver && dev->driver->owner)
+		module_put(dev->driver->owner);
 }
 
 static void spi_nor_restore(struct spi_nor *nor)

Michael Walle

maintainer

2025-07-30 07:50 UTC #4 lore raw

Hi,

Quoted 17 lines

Quoted 8 lines · Khairul Anuar Romli
Quoted 6 lines
From: kromli <[email protected]>
Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:
Quoted 4 lines
As already asked in v2. This needs a (more detailed) description what is going on and what is going wrong.
-michael
Hi,
We just run the following test we observe the crash.

Quoted 7 lines

time dd if=/dev/mtd1 of=out.img bs=1MB count=1000 & echo spi0.0 > /sys/bus/spi/drivers/spi-nor/unbind echo spi0.0 > /sys/bus/spi/drivers/spi-nor/bind
From the observation, the dd is not entirely terminated when the unbind took place. Maybe there is other changes require to ensure the dd operation gets terminated when driver unbind/remove.

I'd expect an analysis what's going wrong in the kernel to judge the correctness of the patch.

Thanks,
-michael

Romli, Khairul Anuar

author

2025-08-21 00:32 UTC #5 lore raw

Hi Michael,

Sorry for taking very long time to reply. Could you advise me what kind of analysis do you want me to provide?

Thanks.

Regards,
Khairul

Quoted 45 lines

-----Original Message-----
From: Michael Walle <[email protected]>
Sent: Wednesday, 30 July, 2025 3:50 PM
To: Romli, Khairul Anuar <[email protected]>; Tudor Ambarus <[email protected]>; Pratyush Yadav <[email protected]>; Miquel Raynal <[email protected]>; Richard Weinberger <[email protected]>; Vignesh Raghavendra <[email protected]>; open list:SPI NOR SUBSYSTEM <[email protected]>; open list <[email protected]>; Gerlach, Matthew <[email protected]>
Subject: Re: [PATCH v3 1/1] mtd: spi-nor: core: Prevent oops during driver removal with active read or write operations
Hi,
Quoted 15 lines
Quoted 8 lines · Khairul Anuar Romli
Quoted 6 lines
From: kromli <[email protected]>
Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:
Quoted 4 lines
As already asked in v2. This needs a (more detailed) description what is going on and what is going wrong.
-michael
Hi,
Quoted 7 lines
We just run the following test we observe the crash.
time dd if=/dev/mtd1 of=out.img bs=1MB count=1000 & echo spi0.0 > /sys/bus/spi/drivers/spi-nor/unbind
echo spi0.0 > /sys/bus/spi/drivers/spi-nor/bind
From the observation, the dd is not entirely terminated when the unbind
took place.
Quoted 2 lines
Maybe there is other changes require to ensure the dd operation gets terminated when driver unbind/remove.
I'd expect an analysis what's going wrong in the kernel to judge the correctness of the patch.
Thanks,
-michael

Michael Walle

maintainer

2025-08-21 06:45 UTC #6 lore raw

Hi,

Quoted 2 lines · Khairul Anuar Romli

Sorry for taking very long time to reply. Could you advise me what kind of analysis do you want me to provide?

Please don't top-post, see [1]. An explanation what is going wrong and why (and no, a backtrace is not an explanation). Why is dev->driver->owner NULL? Shouldn't it be guarded by a lock or something? And esp. why is owner NULL in put_device().

-michael

Quoted 38 lines

Quoted 38 lines
-----Original Message-----
From: Michael Walle <[email protected]>
Sent: Wednesday, 30 July, 2025 3:50 PM
To: Romli, Khairul Anuar <[email protected]>; Tudor Ambarus <[email protected]>; Pratyush Yadav <[email protected]>; Miquel Raynal <[email protected]>; Richard Weinberger <[email protected]>; Vignesh Raghavendra <[email protected]>; open list:SPI NOR SUBSYSTEM <[email protected]>; open list <[email protected]>; Gerlach, Matthew <[email protected]>
Subject: Re: [PATCH v3 1/1] mtd: spi-nor: core: Prevent oops during driver removal with active read or write operations
Hi,
Quoted 15 lines
Quoted 8 lines · Khairul Anuar Romli
Quoted 6 lines
From: kromli <[email protected]>
Ensure that the pointer passed to module_put() in spi_nor_put_device() is not NULL before use. This change adds a guard clause to return early, preventing the kernel crash below when the cadence-qspi driver is removed during a dd operation:
Quoted 4 lines
As already asked in v2. This needs a (more detailed) description what is going on and what is going wrong.
-michael
Hi,
Quoted 7 lines
We just run the following test we observe the crash.
time dd if=/dev/mtd1 of=out.img bs=1MB count=1000 & echo spi0.0 > /sys/bus/spi/drivers/spi-nor/unbind
echo spi0.0 > /sys/bus/spi/drivers/spi-nor/bind
From the observation, the dd is not entirely terminated when the unbind
took place.

Quoted 8 lines

Quoted 8 lines
Quoted 2 lines
Maybe there is other changes require to ensure the dd operation gets terminated when driver unbind/remove.
I'd expect an analysis what's going wrong in the kernel to judge the correctness of the patch.
Thanks,
-michael

[1] https://subspace.kernel.org/etiquette.html