From eece09ec213e93333010bf4c6bb9175b32229c54 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 17 Jul 2011 21:25:03 +0200 Subject: locking: Various static lock initializer fixes The static lock initializers want to be fed the proper name of the lock and not some random string. In mainline random strings are obfuscating the readability of debug output, but for RT they prevent the spinlock substitution. Fix it up. Signed-off-by: Thomas Gleixner --- drivers/char/random.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/char/random.c') diff --git a/drivers/char/random.c b/drivers/char/random.c index 85e81ec1451e..594bda9dcfc8 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -445,7 +445,7 @@ static struct entropy_store input_pool = { .poolinfo = &poolinfo_table[0], .name = "input", .limit = 1, - .lock = __SPIN_LOCK_UNLOCKED(&input_pool.lock), + .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), .pool = input_pool_data }; @@ -454,7 +454,7 @@ static struct entropy_store blocking_pool = { .name = "blocking", .limit = 1, .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(&blocking_pool.lock), + .lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock), .pool = blocking_pool_data }; @@ -462,7 +462,7 @@ static struct entropy_store nonblocking_pool = { .poolinfo = &poolinfo_table[1], .name = "nonblocking", .pull = &input_pool, - .lock = __SPIN_LOCK_UNLOCKED(&nonblocking_pool.lock), + .lock = __SPIN_LOCK_UNLOCKED(nonblocking_pool.lock), .pool = nonblocking_pool_data }; -- cgit v1.2.3 From b980955236922ae6106774511c5c05003d3ad225 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 4 Mar 2013 11:59:12 -0500 Subject: random: fix locking dependency with the tasklist_lock Commit 6133705494bb introduced a circular lock dependency because posix_cpu_timers_exit() is called by release_task(), which is holding a writer lock on tasklist_lock, and this can cause a deadlock since kill_fasync() gets called with nonblocking_pool.lock taken. There's no reason why kill_fasync() needs to be taken while the random pool is locked, so move it out to fix this locking dependency. Signed-off-by: "Theodore Ts'o" Reported-by: Russ Dill Cc: stable@kernel.org --- drivers/char/random.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'drivers/char/random.c') diff --git a/drivers/char/random.c b/drivers/char/random.c index 85e81ec1451e..57d4b152267c 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -852,6 +852,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, int reserved) { unsigned long flags; + int wakeup_write = 0; /* Hold lock while accounting */ spin_lock_irqsave(&r->lock, flags); @@ -873,10 +874,8 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, else r->entropy_count = reserved; - if (r->entropy_count < random_write_wakeup_thresh) { - wake_up_interruptible(&random_write_wait); - kill_fasync(&fasync, SIGIO, POLL_OUT); - } + if (r->entropy_count < random_write_wakeup_thresh) + wakeup_write = 1; } DEBUG_ENT("debiting %zu entropy credits from %s%s\n", @@ -884,6 +883,11 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, spin_unlock_irqrestore(&r->lock, flags); + if (wakeup_write) { + wake_up_interruptible(&random_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } + return nbytes; } -- cgit v1.2.3