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

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[ Upstream commit 08865514805d2de8e7002fa8149c5de3e391f412 ]

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
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: Lokesh Vutla <lokeshvutla@ti.com>
Reported-by: Murali 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lokesh Vutla 2017-02-27 14:28:12 -08:00 committed by Greg Kroah-Hartman
parent d413c3f0bd
commit aaf54d40b8
2 changed files with 2 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
init/initramfs.c
View File

@ -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.

3
init/main.c
View File

@ -70,7 +70,6 @@
#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>
@ -947,8 +946,6 @@ 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) {