The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.8.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git after rh7-3.10.0-229.7.2.vz7.8.6 ------> commit bf86a407af9fa74c7251b62c539f36c141fc4f77 Author: Andrew Vagin <ava...@openvz.org> Date: Thu Oct 15 15:04:13 2015 +0400
ms/prctl: PR_SET_MM -- factor out mmap_sem when updating mm::exe_file The patch is required for CRIU. https://jira.sw.ru/browse/PSBM-39834 From: Cyrill Gorcunov <gorcu...@openvz.org> ML: 71fe97e185040c5dac3216cd54e186dfa534efa0 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 <gorcu...@openvz.org> Cc: Kees Cook <keesc...@chromium.org> Cc: Tejun Heo <t...@kernel.org> Cc: Andrew Vagin <ava...@openvz.org> Cc: Eric W. Biederman <ebied...@xmission.com> Cc: H. Peter Anvin <h...@zytor.com> Acked-by: Serge Hallyn <serge.hal...@canonical.com> Cc: Pavel Emelyanov <xe...@parallels.com> Cc: Vasiliy Kulikov <seg...@openwall.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hir...@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpa...@gmail.com> Cc: Julien Tinnes <j...@google.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Andrew Vagin <ava...@openvz.org> --- kernel/sys.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index a2d5644..cf580a7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2036,12 +2036,14 @@ 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; @@ -2062,8 +2064,6 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) if (err) goto exit; - down_write(&mm->mmap_sem); - /* * Forbid mm->exe_file change if old file still mapped. */ @@ -2075,7 +2075,7 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) if (vma->vm_file && path_equal(&vma->vm_file->f_path, &mm->exe_file->f_path)) - goto exit_unlock; + goto exit; } /* @@ -2086,13 +2086,10 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) */ 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; @@ -2112,8 +2109,12 @@ static int prctl_set_mm(int opt, unsigned long addr, 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; _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel