linux.git/kernel/locking/locktorture.c, branch v6.12.80

locktorture: Fix memory leak in param_set_cpumask()

2025-12-18T12:54:54+00:00

[ Upstream commit e52b43883d084a9af263c573f2a1bd1ca5088389 ]

With CONFIG_CPUMASK_OFFSTACK=y, the 'bind_writers' buffer is allocated via
alloc_cpumask_var() in param_set_cpumask(). But it is not freed, when
setting the module parameter multiple times by sysfs interface or removing
module.

Below kmemleak trace is seen for this issue:

unreferenced object 0xffff888100aabff8 (size 8):
  comm "bash", pid 323, jiffies 4295059233
  hex dump (first 8 bytes):
    07 00 00 00 00 00 00 00                          ........
  backtrace (crc ac50919):
    __kmalloc_node_noprof+0x2e5/0x420
    alloc_cpumask_var_node+0x1f/0x30
    param_set_cpumask+0x26/0xb0 [locktorture]
    param_attr_store+0x93/0x100
    module_attr_store+0x1b/0x30
    kernfs_fop_write_iter+0x114/0x1b0
    vfs_write+0x300/0x410
    ksys_write+0x60/0xd0
    do_syscall_64+0xa4/0x260
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

This issue can be reproduced by:
  insmod locktorture.ko bind_writers=1
  rmmod locktorture

or:
  insmod locktorture.ko bind_writers=1
  echo 2 > /sys/module/locktorture/parameters/bind_writers

Considering that setting the module parameter 'bind_writers' or
'bind_readers' by sysfs interface has no real effect, set the parameter
permissions to 0444. To fix the memory leak when removing module, free
'bind_writers' and 'bind_readers' memory in lock_torture_cleanup().

Fixes: 73e341242483 ("locktorture: Add readers_bind and writers_bind module parameters")
Suggested-by: Zhang Changzhong 
Signed-off-by: Wang Liang 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker 
Signed-off-by: Sasha Levin

locktorture: Add MODULE_DESCRIPTION()

2024-05-30T22:31:45+00:00

Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/locking/locktorture.o

Signed-off-by: Jeff Johnson 
Signed-off-by: Paul E. McKenney

locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains

2023-11-23T06:28:18+00:00

One letter difference is really not enough, so this commit changes
call_rcu_chain to call_rcu_chain_list.

Reported-by: Dan Carpenter 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Neeraj Upadhyay (AMD)

locktorture: Check the correct variable for allocation failure

2023-10-11T13:55:26+00:00

There is a typo so this checks the wrong variable.  "chains" plural vs
"chain" singular.  We already know that "chains" is non-zero.

Fixes: 7f993623e9eb ("locktorture: Add call_rcu_chains module parameter")
Signed-off-by: Dan Carpenter 
Reviewed-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Rename readers_bind/writers_bind to bind_readers/bind_writers

2023-09-24T15:24:02+00:00

This commit renames the readers_bind and writers_bind module parameters
to bind_readers and bind_writers, respectively.  This provides added
clarity via the imperative mode and better organizes the documentation.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Add call_rcu_chains module parameter

2023-09-24T15:24:02+00:00

When running locktorture on large systems, there will normally be
enough RCU activity to ensure that there is a grace period in flight
at all times.  However, on smaller systems, RCU might well be idle the
majority of the time.  This situation can be inconvenient in cases where
the RCU CPU stall warning is part of the debugging process.

This commit therefore adds an call_rcu_chains module parameter to
locktorture, allowing the user to specify the desired number of
self-propagating call_rcu() chains.  For good measure, immediately
before invoking call_rcu(), the self-propagating RCU callback invokes
start_poll_synchronize_rcu() to force the immediate start of a grace
period, with the call_rcu() forcing another to start shortly thereafter.

Booting with locktorture.call_rcu_chains=2 increases the probability
of a stuck locking primitive resulting in an RCU CPU stall warning from
about 25% to nearly 100%.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Add new module parameters to lock_torture_print_module_parms()

2023-09-24T15:24:02+00:00

This commit adds new module parameters to lock_torture_print_module_parms,
and alphabetizes things while in the area.  This change makes locktorture
test results more useful and self-contained.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Add acq_writer_lim to complain about long acquistion times

2023-09-24T15:24:01+00:00

This commit adds a locktorture.acq_writer_lim module parameter that
specifies the maximum number of jiffies that is expected to be consumed
by write-side lock acquisition.  If this limit is exceeded, a WARN_ONCE()
causes a splat.  Note that this limit applies to the main lock acquisition
only, not to any nested acquisitions.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Consolidate "if" statements in lock_torture_writer()

2023-09-24T15:24:01+00:00

There is a pair of adjacent "if" statements with identical conditions in
the lock_torture_writer() function.  This commit therefore combines them.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker

locktorture: Alphabetize torture_param() entries

2023-09-24T15:24:01+00:00

There are getting to be too many module parameters for a random list to be
comfortable, so this commit alphabetizes the list.  Strictly code motion.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker