Re: [RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
On Tuesday 17 January 2017 06:23 PM, Tero Kristo wrote:
> On 17/01/17 13:14, Lokesh Vutla wrote:
>> commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
>> schedule_work() for completing fput(), but did not guarantee calling
>> __fput() after unpacking initramfs. Because of this, there is a
>> possibility that during boot a driver can see ETXTBSY when it tries
>> to load a binary from initramfs as fput() is still pending on that
>> binary. This patch makes sure that fput() is completed after unpacking
>> initramfs.
>
> Good find there.
>
>>
>> Signed-off-by: Lokesh Vutla
>> ---
>>
>> - Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
>> to load a firmware from initramfs during boot. Sometimes loading of this
>> firmware fails with error ETXTBSY. Digging a bit more observed that
>> deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
>> for that file. This is because Unpacking initramfs does a
>> get_write_access(from open) but hasn't done put_write_access(from fput)
>> as it hasn't been scheduled yet.
>>
>> [1]
>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
>>
>>
>> init/initramfs.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/init/initramfs.c b/init/initramfs.c
>> index b32ad7d97ac9..c42c69b48a4b 100644
>> --- a/init/initramfs.c
>> +++ b/init/initramfs.c
>> @@ -18,6 +18,7 @@
>> #include
>> #include
>> #include
>> +#include
>>
>> static ssize_t __init xwrite(int fd, const char *p, size_t count)
>> {
>> @@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
>> * us a chance to load before device_initcalls.
>> */
>> load_default_modules();
>> +flush_delayed_fput();
>
> Shouldn't the flush be called before the load_default_modules() though?
Good point. Will wait for sometime for more comments and then repost it.
Thanks and regards,
Lokesh
Re: [RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
On Tuesday 17 January 2017 06:23 PM, Tero Kristo wrote:
> On 17/01/17 13:14, Lokesh Vutla wrote:
>> commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
>> schedule_work() for completing fput(), but did not guarantee calling
>> __fput() after unpacking initramfs. Because of this, there is a
>> possibility that during boot a driver can see ETXTBSY when it tries
>> to load a binary from initramfs as fput() is still pending on that
>> binary. This patch makes sure that fput() is completed after unpacking
>> initramfs.
>
> Good find there.
>
>>
>> Signed-off-by: Lokesh Vutla
>> ---
>>
>> - Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
>> to load a firmware from initramfs during boot. Sometimes loading of this
>> firmware fails with error ETXTBSY. Digging a bit more observed that
>> deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
>> for that file. This is because Unpacking initramfs does a
>> get_write_access(from open) but hasn't done put_write_access(from fput)
>> as it hasn't been scheduled yet.
>>
>> [1]
>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
>>
>>
>> init/initramfs.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/init/initramfs.c b/init/initramfs.c
>> index b32ad7d97ac9..c42c69b48a4b 100644
>> --- a/init/initramfs.c
>> +++ b/init/initramfs.c
>> @@ -18,6 +18,7 @@
>> #include
>> #include
>> #include
>> +#include
>>
>> static ssize_t __init xwrite(int fd, const char *p, size_t count)
>> {
>> @@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
>> * us a chance to load before device_initcalls.
>> */
>> load_default_modules();
>> +flush_delayed_fput();
>
> Shouldn't the flush be called before the load_default_modules() though?
Good point. Will wait for sometime for more comments and then repost it.
Thanks and regards,
Lokesh
Re: [RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
On 17/01/17 13:14, Lokesh Vutla wrote:
commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
schedule_work() for completing fput(), but did not guarantee calling
__fput() after unpacking initramfs. Because of this, there is a
possibility that during boot a driver can see ETXTBSY when it tries
to load a binary from initramfs as fput() is still pending on that
binary. This patch makes sure that fput() is completed after unpacking
initramfs.
Good find there.
Signed-off-by: Lokesh Vutla
---
- Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
to load a firmware from initramfs during boot. Sometimes loading of this
firmware fails with error ETXTBSY. Digging a bit more observed that
deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
for that file. This is because Unpacking initramfs does a
get_write_access(from open) but hasn't done put_write_access(from fput)
as it hasn't been scheduled yet.
[1]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
init/initramfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/init/initramfs.c b/init/initramfs.c
index b32ad7d97ac9..c42c69b48a4b 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
static ssize_t __init xwrite(int fd, const char *p, size_t count)
{
@@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
* us a chance to load before device_initcalls.
*/
load_default_modules();
+ flush_delayed_fput();
Shouldn't the flush be called before the load_default_modules() though?
-Tero
Re: [RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
On 17/01/17 13:14, Lokesh Vutla wrote:
commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
schedule_work() for completing fput(), but did not guarantee calling
__fput() after unpacking initramfs. Because of this, there is a
possibility that during boot a driver can see ETXTBSY when it tries
to load a binary from initramfs as fput() is still pending on that
binary. This patch makes sure that fput() is completed after unpacking
initramfs.
Good find there.
Signed-off-by: Lokesh Vutla
---
- Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
to load a firmware from initramfs during boot. Sometimes loading of this
firmware fails with error ETXTBSY. Digging a bit more observed that
deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
for that file. This is because Unpacking initramfs does a
get_write_access(from open) but hasn't done put_write_access(from fput)
as it hasn't been scheduled yet.
[1]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
init/initramfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/init/initramfs.c b/init/initramfs.c
index b32ad7d97ac9..c42c69b48a4b 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
static ssize_t __init xwrite(int fd, const char *p, size_t count)
{
@@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
* us a chance to load before device_initcalls.
*/
load_default_modules();
+ flush_delayed_fput();
Shouldn't the flush be called before the load_default_modules() though?
-Tero
[RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
schedule_work() for completing fput(), but did not guarantee calling
__fput() after unpacking initramfs. Because of this, there is a
possibility that during boot a driver can see ETXTBSY when it tries
to load a binary from initramfs as fput() is still pending on that
binary. This patch makes sure that fput() is completed after unpacking
initramfs.
Signed-off-by: Lokesh Vutla
---
- Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
to load a firmware from initramfs during boot. Sometimes loading of this
firmware fails with error ETXTBSY. Digging a bit more observed that
deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
for that file. This is because Unpacking initramfs does a
get_write_access(from open) but hasn't done put_write_access(from fput)
as it hasn't been scheduled yet.
[1]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
init/initramfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/init/initramfs.c b/init/initramfs.c
index b32ad7d97ac9..c42c69b48a4b 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
static ssize_t __init xwrite(int fd, const char *p, size_t count)
{
@@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
* us a chance to load before device_initcalls.
*/
load_default_modules();
+ flush_delayed_fput();
}
return 0;
}
--
2.11.0
[RFC PATCH] initramfs: finish fput() before accessing any binary from initramfs
commit 4a9d4b024a31 ("switch fput to task_work_add") implements a
schedule_work() for completing fput(), but did not guarantee calling
__fput() after unpacking initramfs. Because of this, there is a
possibility that during boot a driver can see ETXTBSY when it tries
to load a binary from initramfs as fput() is still pending on that
binary. This patch makes sure that fput() is completed after unpacking
initramfs.
Signed-off-by: Lokesh Vutla
---
- Reproduced on TI K2HK EVM. K2HK Queue Manager subsystem driver[1] tries
to load a firmware from initramfs during boot. Sometimes loading of this
firmware fails with error ETXTBSY. Digging a bit more observed that
deny_write_access() is returning ETXTBSY as inode->i_writecount is > 0
for that file. This is because Unpacking initramfs does a
get_write_access(from open) but hasn't done put_write_access(from fput)
as it hasn't been scheduled yet.
[1]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/ti/knav_qmss_queue.c
init/initramfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/init/initramfs.c b/init/initramfs.c
index b32ad7d97ac9..c42c69b48a4b 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
static ssize_t __init xwrite(int fd, const char *p, size_t count)
{
@@ -652,6 +653,7 @@ static int __init populate_rootfs(void)
* us a chance to load before device_initcalls.
*/
load_default_modules();
+ flush_delayed_fput();
}
return 0;
}
--
2.11.0
