The patch titled
Subject: proc: don't do dummy rcu_read_lock/rcu_read_unlock on error path
has been added to the -mm tree. Its filename is
proc-dont-do-dummy-rcu_read_lock-rcu_read_unlock-on-error-path.patch
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From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: don't do dummy rcu_read_lock/rcu_read_unlock on error path
rcu_read_lock()/rcu_read_unlock() is nop for TINY_RCU, but is not a nop
for, say, PREEMPT_RCU.
proc_fill_cache() is called without RCU lock, there is no need to
lock/unlock on error path, simply jump out of the loop.
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff -puN fs/proc/base.c~proc-dont-do-dummy-rcu_read_lock-rcu_read_unlock-on-error-path fs/proc/base.c
--- a/fs/proc/base.c~proc-dont-do-dummy-rcu_read_lock-rcu_read_unlock-on-error-path
+++ a/fs/proc/base.c
@@ -1941,21 +1941,22 @@ static int proc_readfd_common(struct fil
fd++, filp->f_pos++) {
char name[PROC_NUMBUF];
int len;
+ int rv;
if (!fcheck_files(files, fd))
continue;
rcu_read_unlock();
len = snprintf(name, sizeof(name), "%d", fd);
- if (proc_fill_cache(filp, dirent, filldir,
- name, len, instantiate,
- p, &fd) < 0) {
- rcu_read_lock();
- break;
- }
+ rv = proc_fill_cache(filp, dirent, filldir,
+ name, len, instantiate, p,
+ &fd);
+ if (rv < 0)
+ goto out_fd_loop;
rcu_read_lock();
}
rcu_read_unlock();
+out_fd_loop:
put_files_struct(files);
}
out:
_
Subject: Subject: proc: don't do dummy rcu_read_lock/rcu_read_unlock on error path
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
kstrtox-mark-const-init-data-with-__initconst-instead-of-__initdata.patch
proc-clean-up-proc-pid-environ-handling.patch
proc-unify-ptrace_may_access-locking-code.patch
proc-remove-mm_for_maps.patch
proc-use-mm_access-instead-of-ptrace_may_access.patch
proc-dont-do-dummy-rcu_read_lock-rcu_read_unlock-on-error-path.patch
proc-use-is_err_or_null.patch
syscalls-x86-add-__nr_kcmp-syscall-v8.patch
c-r-procfs-add-arg_start-end-env_start-end-and-exit_code-members-to-proc-pid-stat.patch
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