From aecd42df6d399346fd8e5551dd8878338f214ec1 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Mon, 6 Apr 2020 20:09:54 -0700 Subject: lib/test_lockup.c: add parameters for locking generic vfs locks file_path= defines file or directory to open lock_inode=Y set lock_rwsem_ptr to inode->i_rwsem lock_mapping=Y set lock_rwsem_ptr to mapping->i_mmap_rwsem lock_sb_umount=Y set lock_rwsem_ptr to sb->s_umount This gives safe and simple way to see how system reacts to contention of common vfs locks and how syscalls depend on them directly or indirectly. For example to block s_umount for 60 seconds: # modprobe test_lockup file_path=. lock_sb_umount time_secs=60 state=S This is useful for checking/testing scalability issues like this: https://lore.kernel.org/lkml/158497590858.7371.9311902565121473436.stgit@buzz/ Signed-off-by: Konstantin Khlebnikov Signed-off-by: Andrew Morton Cc: Colin Ian King Cc: Greg Kroah-Hartman Cc: Guenter Roeck Cc: Kees Cook Cc: Peter Zijlstra Cc: Petr Mladek Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Steven Rostedt Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz Signed-off-by: Linus Torvalds --- lib/test_lockup.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'lib') diff --git a/lib/test_lockup.c b/lib/test_lockup.c index 83683ec1f429..ea09ca335b21 100644 --- a/lib/test_lockup.c +++ b/lib/test_lockup.c @@ -14,6 +14,7 @@ #include #include #include +#include static unsigned int time_secs; module_param(time_secs, uint, 0600); @@ -140,6 +141,24 @@ static bool reallocate_pages; module_param(reallocate_pages, bool, 0400); MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations"); +struct file *test_file; +struct inode *test_inode; +static char test_file_path[256]; +module_param_string(file_path, test_file_path, sizeof(test_file_path), 0400); +MODULE_PARM_DESC(file_path, "file path to test"); + +static bool test_lock_inode; +module_param_named(lock_inode, test_lock_inode, bool, 0400); +MODULE_PARM_DESC(lock_inode, "lock file -> inode -> i_rwsem"); + +static bool test_lock_mapping; +module_param_named(lock_mapping, test_lock_mapping, bool, 0400); +MODULE_PARM_DESC(lock_mapping, "lock file -> mapping -> i_mmap_rwsem"); + +static bool test_lock_sb_umount; +module_param_named(lock_sb_umount, test_lock_sb_umount, bool, 0400); +MODULE_PARM_DESC(lock_sb_umount, "lock file -> sb -> s_umount"); + static atomic_t alloc_pages_failed = ATOMIC_INIT(0); static atomic64_t max_lock_wait = ATOMIC64_INIT(0); @@ -490,6 +509,29 @@ static int __init test_lockup_init(void) return -EINVAL; } + if (test_file_path[0]) { + test_file = filp_open(test_file_path, O_RDONLY, 0); + if (IS_ERR(test_file)) { + pr_err("cannot find file_path\n"); + return -EINVAL; + } + test_inode = file_inode(test_file); + } else if (test_lock_inode || + test_lock_mapping || + test_lock_sb_umount) { + pr_err("no file to lock\n"); + return -EINVAL; + } + + if (test_lock_inode && test_inode) + lock_rwsem_ptr = (unsigned long)&test_inode->i_rwsem; + + if (test_lock_mapping && test_file && test_file->f_mapping) + lock_rwsem_ptr = (unsigned long)&test_file->f_mapping->i_mmap_rwsem; + + if (test_lock_sb_umount && test_inode) + lock_rwsem_ptr = (unsigned long)&test_inode->i_sb->s_umount; + pr_notice("START pid=%d time=%u +%u ns cooldown=%u +%u ns iterations=%u state=%s %s%s%s%s%s%s%s%s%s%s%s\n", main_task->pid, time_secs, time_nsecs, cooldown_secs, cooldown_nsecs, iterations, state, @@ -542,6 +584,9 @@ static int __init test_lockup_init(void) pr_notice("FINISH in %llu ns\n", local_clock() - test_start); + if (test_file) + fput(test_file); + if (signal_pending(main_task)) return -EINTR; -- cgit v1.2.3