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[ Upstream commite52b43883d] 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:73e3412424("locktorture: Add readers_bind and writers_bind module parameters") Suggested-by: Zhang Changzhong <zhangchangzhong@huawei.com> Signed-off-by: Wang Liang <wangliang74@huawei.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>