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Commit 08865514 authored by Lokesh Vutla's avatar Lokesh Vutla Committed by Linus Torvalds
Browse files

initramfs: finish fput() before accessing any binary from initramfs 

Commit 4a9d4b02 ("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
and removes the call to flush_delayed_fput() in kernel_init() which
happens very late after unpacking initramfs.

Link: http://lkml.kernel.org/r/20170201140540.22051-1-lokeshvutla@ti.com


Signed-off-by: default avatarLokesh Vutla <lokeshvutla@ti.com>
Reported-by: default avatarMurali Karicheri <m-karicheri2@ti.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7bcae826

init/initramfs.c

+2 −0
Original line number Diff line number Diff line
@@ -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)

{
@@ -647,6 +648,7 @@ static int __init populate_rootfs(void) 
			printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);

		free_initrd();

#endif

		flush_delayed_fput();

		/*

		 * Try loading default modules from initramfs.  This gives

		 * us a chance to load before device_initcalls.

init/main.c

+0 −3
Original line number Diff line number Diff line
@@ -71,7 +71,6 @@ 
#include <linux/shmem_fs.h>

#include <linux/slab.h>

#include <linux/perf_event.h>

#include <linux/file.h>

#include <linux/ptrace.h>

#include <linux/blkdev.h>

#include <linux/elevator.h>
@@ -960,8 +959,6 @@ static int __ref kernel_init(void *unused) 
	system_state = SYSTEM_RUNNING;

	numa_default_policy();



	flush_delayed_fput();



	rcu_end_inkernel_boot();



	if (ramdisk_execute_command) {