This is a note to let you know that I've just added the patch titled
locking/locktorture: Fix num reader/writer corner cases
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: locking-locktorture-fix-num-reader-writer-corner-cases.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Fri Mar 16 15:11:08 CET 2018
From: Davidlohr Bueso dave@stgolabs.net Date: Mon, 15 May 2017 02:07:23 -0700 Subject: locking/locktorture: Fix num reader/writer corner cases
From: Davidlohr Bueso dave@stgolabs.net
[ Upstream commit 2ce77d16db4240dd2e422fc0a5c26d3e2ec03446 ]
Things can explode for locktorture if the user does combinations of nwriters_stress=0 nreaders_stress=0. Fix this by not assuming we always want to torture writer threads.
Reported-by: Jeremy Linton jeremy.linton@arm.com Signed-off-by: Davidlohr Bueso dbueso@suse.de Signed-off-by: Paul E. McKenney paulmck@linux.vnet.ibm.com Reviewed-by: Jeremy Linton jeremy.linton@arm.com Tested-by: Jeremy Linton jeremy.linton@arm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/locking/locktorture.c | 76 ++++++++++++++++++++++++------------------- 1 file changed, 44 insertions(+), 32 deletions(-)
--- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -715,8 +715,7 @@ static void __torture_print_stats(char * { bool fail = 0; int i, n_stress; - long max = 0; - long min = statp[0].n_lock_acquired; + long max = 0, min = statp ? statp[0].n_lock_acquired : 0; long long sum = 0;
n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; @@ -823,7 +822,7 @@ static void lock_torture_cleanup(void) * such, only perform the underlying torture-specific cleanups, * and avoid anything related to locktorture. */ - if (!cxt.lwsa) + if (!cxt.lwsa && !cxt.lrsa) goto end;
if (writer_tasks) { @@ -898,6 +897,13 @@ static int __init lock_torture_init(void firsterr = -EINVAL; goto unwind; } + + if (nwriters_stress == 0 && nreaders_stress == 0) { + pr_alert("lock-torture: must run at least one locking thread\n"); + firsterr = -EINVAL; + goto unwind; + } + if (cxt.cur_ops->init) cxt.cur_ops->init();
@@ -921,17 +927,19 @@ static int __init lock_torture_init(void #endif
/* Initialize the statistics so that each run gets its own numbers. */ + if (nwriters_stress) { + lock_is_write_held = 0; + cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL); + if (cxt.lwsa == NULL) { + VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); + firsterr = -ENOMEM; + goto unwind; + }
- lock_is_write_held = 0; - cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL); - if (cxt.lwsa == NULL) { - VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); - firsterr = -ENOMEM; - goto unwind; - } - for (i = 0; i < cxt.nrealwriters_stress; i++) { - cxt.lwsa[i].n_lock_fail = 0; - cxt.lwsa[i].n_lock_acquired = 0; + for (i = 0; i < cxt.nrealwriters_stress; i++) { + cxt.lwsa[i].n_lock_fail = 0; + cxt.lwsa[i].n_lock_acquired = 0; + } }
if (cxt.cur_ops->readlock) { @@ -948,19 +956,21 @@ static int __init lock_torture_init(void cxt.nrealreaders_stress = cxt.nrealwriters_stress; }
- lock_is_read_held = 0; - cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL); - if (cxt.lrsa == NULL) { - VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); - firsterr = -ENOMEM; - kfree(cxt.lwsa); - cxt.lwsa = NULL; - goto unwind; - } - - for (i = 0; i < cxt.nrealreaders_stress; i++) { - cxt.lrsa[i].n_lock_fail = 0; - cxt.lrsa[i].n_lock_acquired = 0; + if (nreaders_stress) { + lock_is_read_held = 0; + cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL); + if (cxt.lrsa == NULL) { + VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); + firsterr = -ENOMEM; + kfree(cxt.lwsa); + cxt.lwsa = NULL; + goto unwind; + } + + for (i = 0; i < cxt.nrealreaders_stress; i++) { + cxt.lrsa[i].n_lock_fail = 0; + cxt.lrsa[i].n_lock_acquired = 0; + } } }
@@ -990,12 +1000,14 @@ static int __init lock_torture_init(void goto unwind; }
- writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]), - GFP_KERNEL); - if (writer_tasks == NULL) { - VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory"); - firsterr = -ENOMEM; - goto unwind; + if (nwriters_stress) { + writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]), + GFP_KERNEL); + if (writer_tasks == NULL) { + VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory"); + firsterr = -ENOMEM; + goto unwind; + } }
if (cxt.cur_ops->readlock) {
Patches currently in stable-queue which might be from dave@stgolabs.net are
queue-4.15/locking-locktorture-fix-num-reader-writer-corner-cases.patch