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 <lokeshvu...@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