The patch titled
Subject: prctl: PR_SET_MM -- factor out mmap_sem when updating mm::exe_file
has been added to the -mm tree. Its filename is
prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Subject: prctl: PR_SET_MM -- factor out mmap_sem when updating mm::exe_file
Instead of taking mm->mmap_sem inside prctl_set_mm_exe_file() move it out
and rename the helper to prctl_set_mm_exe_file_locked(). This will allow
to reuse this function in a next patch.
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Andrew Vagin <avagin@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Julien Tinnes <jln@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sys.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff -puN kernel/sys.c~prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file kernel/sys.c
--- a/kernel/sys.c~prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file
+++ a/kernel/sys.c
@@ -1628,12 +1628,14 @@ SYSCALL_DEFINE1(umask, int, mask)
return mask;
}
-static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
+static int prctl_set_mm_exe_file_locked(struct mm_struct *mm, unsigned int fd)
{
struct fd exe;
struct inode *inode;
int err;
+ VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+
exe = fdget(fd);
if (!exe.file)
return -EBADF;
@@ -1654,8 +1656,6 @@ static int prctl_set_mm_exe_file(struct
if (err)
goto exit;
- down_write(&mm->mmap_sem);
-
/*
* Forbid mm->exe_file change if old file still mapped.
*/
@@ -1667,7 +1667,7 @@ static int prctl_set_mm_exe_file(struct
if (vma->vm_file &&
path_equal(&vma->vm_file->f_path,
&mm->exe_file->f_path))
- goto exit_unlock;
+ goto exit;
}
/*
@@ -1678,13 +1678,10 @@ static int prctl_set_mm_exe_file(struct
*/
err = -EPERM;
if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
- goto exit_unlock;
+ goto exit;
err = 0;
set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */
-exit_unlock:
- up_write(&mm->mmap_sem);
-
exit:
fdput(exe);
return err;
@@ -1703,8 +1700,12 @@ static int prctl_set_mm(int opt, unsigne
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
- if (opt == PR_SET_MM_EXE_FILE)
- return prctl_set_mm_exe_file(mm, (unsigned int)addr);
+ if (opt == PR_SET_MM_EXE_FILE) {
+ down_write(&mm->mmap_sem);
+ error = prctl_set_mm_exe_file_locked(mm, (unsigned int)addr);
+ up_write(&mm->mmap_sem);
+ return error;
+ }
if (addr >= TASK_SIZE || addr < mmap_min_addr)
return -EINVAL;
_
Patches currently in -mm which might be from gorcunov@xxxxxxxxxx are
mm-introduce-check_data_rlimit-helper-v2.patch
mm-use-may_adjust_brk-helper.patch
prctl-pr_set_mm-factor-out-mmap_sem-when-update-mm-exe_file.patch
prctl-pr_set_mm-introduce-pr_set_mm_map-operation-v3.patch
prctl-pr_set_mm-introduce-pr_set_mm_map-operation-v3-fix.patch
fs-proc-task_mmuc-dont-use-task-mm-in-m_start-and-show_map.patch
fs-proc-task_mmuc-unify-simplify-do_maps_open-and-numa_maps_open.patch
proc-introduce-proc_mem_open.patch
fs-proc-task_mmuc-shift-mm_access-from-m_start-to-proc_maps_open.patch
fs-proc-task_mmuc-simplify-the-vma_stop-logic.patch
fs-proc-task_mmuc-cleanup-the-tail_vma-horror-in-m_next.patch
fs-proc-task_mmuc-shift-priv-task-=-null-from-m_start-to-m_stop.patch
fs-proc-task_mmuc-kill-the-suboptimal-and-confusing-m-version-logic.patch
fs-proc-task_mmuc-simplify-m_start-to-make-it-readable.patch
fs-proc-task_mmuc-introduce-m_next_vma-helper.patch
fs-proc-task_mmuc-reintroduce-m-version-logic.patch
fs-proc-task_mmuc-update-m-version-in-the-main-loop-in-m_start.patch
fs-proc-task_nommuc-change-maps_open-to-use-__seq_open_private.patch
fs-proc-task_nommuc-shift-mm_access-from-m_start-to-proc_maps_open.patch
fs-proc-task_nommuc-dont-use-priv-task-mm.patch
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