| Message ID | 20170117111456.2269-1-lokeshvutla@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <lokeshvutla@ti.com> > --- > > - 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 <linux/dirent.h> > #include <linux/syscalls.h> > #include <linux/utime.h> > +#include <linux/file.h> > > 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
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 <lokeshvutla@ti.com> >> --- >> >> - 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 <linux/dirent.h> >> #include <linux/syscalls.h> >> #include <linux/utime.h> >> +#include <linux/file.h> >> >> 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
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 <linux/dirent.h> #include <linux/syscalls.h> #include <linux/utime.h> +#include <linux/file.h> 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; }
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 <lokeshvutla@ti.com> --- - 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(+)