aboutsummaryrefslogtreecommitdiff
path: root/fs/ioprio.c
diff options
context:
space:
mode:
authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2010-11-09 21:26:56 +0100
committerJens Axboe <jaxboe@fusionio.com>2010-11-10 14:40:53 +0100
commitf85acd81aa623e3dcf268c90e5cd8ecf36830984 (patch)
treecb6baded85812573ad2f42bfe47b9d185b61918b /fs/ioprio.c
parent1447399b3e34af016c368b4178db7ef0e04e15b0 (diff)
downloadlinux-f85acd81aa623e3dcf268c90e5cd8ecf36830984.tar.gz
ioprio: rcu_read_lock/unlock protect find_task_by_vpid call (V2)
Commit 4221a9918e38b7494cee341dda7b7b4bb8c04bde "Add RCU check for find_task_by_vpid()" introduced rcu_lockdep_assert to find_task_by_pid_ns= Assertion failed in sys_ioprio_get. The patch is fixing assertion failure in ioprio_set as well. kernel/pid.c:419 invoked rcu_dereference_check() without protection! stack backtrace: Pid: 4254, comm: iotop Not tainted Call Trace: [<ffffffff810656f2>] lockdep_rcu_dereference+0xaa/0xb2 [<ffffffff81053c67>] find_task_by_pid_ns+0x4f/0x68 [<ffffffff81053c9d>] find_task_by_vpid+0x1d/0x1f [<ffffffff811104e2>] sys_ioprio_get+0x50/0x2da [<ffffffff81002182>] system_call_fastpath+0x16/0x1b V2: rcu critical section expanded according to comment by Paul E. McKenney Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'fs/ioprio.c')
-rw-r--r--fs/ioprio.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/ioprio.c b/fs/ioprio.c
index 8def14e24c3..2f7d05c8992 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -111,12 +111,14 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
read_lock(&tasklist_lock);
switch (which) {
case IOPRIO_WHO_PROCESS:
+ rcu_read_lock();
if (!who)
p = current;
else
p = find_task_by_vpid(who);
if (p)
ret = set_task_ioprio(p, ioprio);
+ rcu_read_unlock();
break;
case IOPRIO_WHO_PGRP:
if (!who)
@@ -205,12 +207,14 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
read_lock(&tasklist_lock);
switch (which) {
case IOPRIO_WHO_PROCESS:
+ rcu_read_lock();
if (!who)
p = current;
else
p = find_task_by_vpid(who);
if (p)
ret = get_task_ioprio(p);
+ rcu_read_unlock();
break;
case IOPRIO_WHO_PGRP:
if (!who)