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| author | Thomas Gleixner <tglx@linutronix.de> | 2009-12-01 14:02:00 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2010-02-21 20:20:06 +0100 |
| commit | a95bd8cf879ef7b70fb441f9593459425746cb13 (patch) | |
| tree | 515b966bd430166285f40b17b512c8e0afb5d8f1 | |
| parent | 5f854cfc024622e4aae14d7cf422f6ff86278688 (diff) | |
| download | lwn-a95bd8cf879ef7b70fb441f9593459425746cb13.tar.gz lwn-a95bd8cf879ef7b70fb441f9593459425746cb13.zip | |
futex: Protect pid lookup in compat code with RCU
find_task_by_vpid() in compat_sys_get_robust_list() does not require
tasklist_lock. It can be protected with rcu_read_lock as done in
sys_get_robust_list() already.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
| -rw-r--r-- | kernel/futex_compat.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c index 235716556bf1..d49afb2395e5 100644 --- a/kernel/futex_compat.c +++ b/kernel/futex_compat.c @@ -146,7 +146,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, struct task_struct *p; ret = -ESRCH; - read_lock(&tasklist_lock); + rcu_read_lock(); p = find_task_by_vpid(pid); if (!p) goto err_unlock; @@ -157,7 +157,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, !capable(CAP_SYS_PTRACE)) goto err_unlock; head = p->compat_robust_list; - read_unlock(&tasklist_lock); + rcu_read_unlock(); } if (put_user(sizeof(*head), len_ptr)) @@ -165,7 +165,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, return put_user(ptr_to_compat(head), head_ptr); err_unlock: - read_unlock(&tasklist_lock); + rcu_read_unlock(); return ret; } |