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| author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2010-11-09 21:26:56 +0100 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2010-11-10 14:40:53 +0100 |
| commit | f85acd81aa623e3dcf268c90e5cd8ecf36830984 (patch) | |
| tree | cb6baded85812573ad2f42bfe47b9d185b61918b /fs | |
| parent | ioprio: fix RCU locking around task dereference (diff) | |
| download | linux-f85acd81aa623e3dcf268c90e5cd8ecf36830984.tar.xz linux-f85acd81aa623e3dcf268c90e5cd8ecf36830984.zip | |
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')
| -rw-r--r-- | fs/ioprio.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/ioprio.c b/fs/ioprio.c index 8def14e24c37..2f7d05c89922 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) |