diff mbox series

[PREEMPT_RT,2/2] blktrace: switch trace spinlock to a raw spinlock

Message ID 20211210204156.96336-3-wander@redhat.com
State Superseded
Headers show
Series Fix warnings in blktrace | expand

Commit Message

Wander Lairson Costa Dec. 10, 2021, 8:41 p.m. UTC 
TRACE_EVENT disables preemption before calling the callback. Because of
that blktrace triggers the following bug under PREEMPT_RT:

 BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:35
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 119, name: kworker/u2:2
 5 locks held by kworker/u2:2/119:
  #0: ffff8c2e4a88f538 ((wq_completion)xfs-cil/dm-0){+.+.}-{0:0}, at: process_one_work+0x200/0x450
  #1: ffffab3840ac7e68 ((work_completion)(&cil->xc_push_work)){+.+.}-{0:0}, at: process_one_work+0x200/0x450
  #2: ffff8c2e4a887128 (&cil->xc_ctx_lock){++++}-{3:3}, at: xlog_cil_push_work+0xb7/0x670 [xfs]
  #3: ffffffffa6a63780 (rcu_read_lock){....}-{1:2}, at: blk_add_trace_bio+0x0/0x1f0
  #4: ffffffffa6610620 (running_trace_lock){+.+.}-{2:2}, at: __blk_add_trace+0x3ef/0x480
 Preemption disabled at:
 [<ffffffffa4d35c05>] migrate_enable+0x45/0x140
 CPU: 0 PID: 119 Comm: kworker/u2:2 Kdump: loaded Not tainted 5.14.0-25.rt21.25.light.el9.x86_64+debug #1
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 Workqueue: xfs-cil/dm-0 xlog_cil_push_work [xfs]
 Call Trace:
  ? migrate_enable+0x45/0x140
  dump_stack_lvl+0x57/0x7d
  ___might_sleep.cold+0xe3/0xf7
  rt_spin_lock+0x3a/0xd0
  ? __blk_add_trace+0x3ef/0x480
  __blk_add_trace+0x3ef/0x480
  blk_add_trace_bio+0x18d/0x1f0
  trace_block_bio_queue+0xb5/0x150
  submit_bio_checks+0x1f0/0x520
  ? sched_clock_cpu+0xb/0x100
  submit_bio_noacct+0x30/0x1d0
  ? bio_associate_blkg+0x66/0x190
  xlog_cil_push_work+0x1b6/0x670 [xfs]
  ? register_lock_class+0x43/0x4f0
  ? xfs_swap_extents+0x5f0/0x5f0 [xfs]
  process_one_work+0x275/0x450
  ? process_one_work+0x200/0x450
  worker_thread+0x55/0x3c0
  ? process_one_work+0x450/0x450
  kthread+0x188/0x1a0
  ? set_kthread_struct+0x40/0x40
  ret_from_fork+0x22/0x30

To avoid this bug, we switch the trace lock to a raw spinlock.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
---
 kernel/trace/blktrace.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Comments

kernel test robot Dec. 11, 2021, 3:06 a.m. UTC | #1 
Hi Wander,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linux/master linus/master v5.16-rc4]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211211-044405
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: nds32-randconfig-r012-20211210 (https://download.01.org/0day-ci/archive/20211211/202112111053.CFUB5OjZ-lkp@intel.com/config)
compiler: nds32le-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/78ab0023d3b1ba3f3dc5703b4d4fac1dd24aa0c2
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211211-044405
        git checkout 78ab0023d3b1ba3f3dc5703b4d4fac1dd24aa0c2
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash drivers/vfio/ kernel/trace/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   kernel/trace/blktrace.c: In function '__trace_note_message':
   kernel/trace/blktrace.c:148:63: warning: parameter 'blkcg' set but not used [-Wunused-but-set-parameter]
     148 | void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
         |                                                 ~~~~~~~~~~~~~~^~~~~
   kernel/trace/blktrace.c: In function 'blk_trace_remove_queue':
>> kernel/trace/blktrace.c:1611:31: error: passing argument 1 of 'spin_lock_irq' from incompatible pointer type [-Werror=incompatible-pointer-types]
    1611 |                 spin_lock_irq(&running_trace_lock);
         |                               ^~~~~~~~~~~~~~~~~~~
         |                               |
         |                               raw_spinlock_t * {aka struct raw_spinlock *}
   In file included from include/linux/wait.h:9,
                    from include/linux/pid.h:6,
                    from include/linux/sched.h:14,
                    from include/linux/blkdev.h:5,
                    from kernel/trace/blktrace.c:10:
   include/linux/spinlock.h:372:55: note: expected 'spinlock_t *' {aka 'struct spinlock *'} but argument is of type 'raw_spinlock_t *' {aka 'struct raw_spinlock *'}
     372 | static __always_inline void spin_lock_irq(spinlock_t *lock)
         |                                           ~~~~~~~~~~~~^~~~
>> kernel/trace/blktrace.c:1613:33: error: passing argument 1 of 'spin_unlock_irq' from incompatible pointer type [-Werror=incompatible-pointer-types]
    1613 |                 spin_unlock_irq(&running_trace_lock);
         |                                 ^~~~~~~~~~~~~~~~~~~
         |                                 |
         |                                 raw_spinlock_t * {aka struct raw_spinlock *}
   In file included from include/linux/wait.h:9,
                    from include/linux/pid.h:6,
                    from include/linux/sched.h:14,
                    from include/linux/blkdev.h:5,
                    from kernel/trace/blktrace.c:10:
   include/linux/spinlock.h:397:57: note: expected 'spinlock_t *' {aka 'struct spinlock *'} but argument is of type 'raw_spinlock_t *' {aka 'struct raw_spinlock *'}
     397 | static __always_inline void spin_unlock_irq(spinlock_t *lock)
         |                                             ~~~~~~~~~~~~^~~~
   cc1: some warnings being treated as errors


vim +/spin_lock_irq +1611 kernel/trace/blktrace.c

c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1599  
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1600  static int blk_trace_remove_queue(struct request_queue *q)
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1601  {
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1602  	struct blk_trace *bt;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1603  
c3dbe541ef7775 kernel/trace/blktrace.c Jan Kara                 2020-06-05  1604  	bt = rcu_replace_pointer(q->blk_trace, NULL,
85e0cbbb8a7953 kernel/trace/blktrace.c Luis Chamberlain         2020-06-19  1605  				 lockdep_is_held(&q->debugfs_mutex));
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1606  	if (bt == NULL)
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1607  		return -EINVAL;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1608  
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1609  	if (bt->trace_state == Blktrace_running) {
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1610  		bt->trace_state = Blktrace_stopped;
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23 @1611  		spin_lock_irq(&running_trace_lock);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1612  		list_del_init(&bt->running_list);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23 @1613  		spin_unlock_irq(&running_trace_lock);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1614  		relay_flush(bt->rchan);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1615  	}
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1616  
a6da0024ffc19e kernel/trace/blktrace.c Jens Axboe               2017-11-05  1617  	put_probe_ref();
c780e86dd48ef6 kernel/trace/blktrace.c Jan Kara                 2020-02-06  1618  	synchronize_rcu();
ad5dd5493a55e4 kernel/trace/blktrace.c Li Zefan                 2009-03-27  1619  	blk_trace_free(bt);
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1620  	return 0;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1621  }
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1622  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Dec. 11, 2021, 10:09 a.m. UTC | #2 
Hi Wander,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linux/master linus/master v5.16-rc4]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211211-044405
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: arm64-randconfig-r014-20211210 (https://download.01.org/0day-ci/archive/20211211/202112111754.ivCXr0cu-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 097a1cb1d5ebb3a0ec4bcaed8ba3ff6a8e33c00a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/78ab0023d3b1ba3f3dc5703b4d4fac1dd24aa0c2
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Wander-Lairson-Costa/Fix-warnings-in-blktrace/20211211-044405
        git checkout 78ab0023d3b1ba3f3dc5703b4d4fac1dd24aa0c2
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash kernel/trace/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> kernel/trace/blktrace.c:1611:17: error: incompatible pointer types passing 'raw_spinlock_t *' (aka 'struct raw_spinlock *') to parameter of type 'spinlock_t *' (aka 'struct spinlock *') [-Werror,-Wincompatible-pointer-types]
                   spin_lock_irq(&running_trace_lock);
                                 ^~~~~~~~~~~~~~~~~~~
   include/linux/spinlock.h:372:55: note: passing argument to parameter 'lock' here
   static __always_inline void spin_lock_irq(spinlock_t *lock)
                                                         ^
   kernel/trace/blktrace.c:1613:19: error: incompatible pointer types passing 'raw_spinlock_t *' (aka 'struct raw_spinlock *') to parameter of type 'spinlock_t *' (aka 'struct spinlock *') [-Werror,-Wincompatible-pointer-types]
                   spin_unlock_irq(&running_trace_lock);
                                   ^~~~~~~~~~~~~~~~~~~
   include/linux/spinlock.h:397:57: note: passing argument to parameter 'lock' here
   static __always_inline void spin_unlock_irq(spinlock_t *lock)
                                                           ^
   2 errors generated.


vim +1611 kernel/trace/blktrace.c

c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1599  
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1600  static int blk_trace_remove_queue(struct request_queue *q)
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1601  {
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1602  	struct blk_trace *bt;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1603  
c3dbe541ef7775 kernel/trace/blktrace.c Jan Kara                 2020-06-05  1604  	bt = rcu_replace_pointer(q->blk_trace, NULL,
85e0cbbb8a7953 kernel/trace/blktrace.c Luis Chamberlain         2020-06-19  1605  				 lockdep_is_held(&q->debugfs_mutex));
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1606  	if (bt == NULL)
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1607  		return -EINVAL;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1608  
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1609  	if (bt->trace_state == Blktrace_running) {
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1610  		bt->trace_state = Blktrace_stopped;
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23 @1611  		spin_lock_irq(&running_trace_lock);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1612  		list_del_init(&bt->running_list);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1613  		spin_unlock_irq(&running_trace_lock);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1614  		relay_flush(bt->rchan);
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1615  	}
5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng             2021-09-23  1616  
a6da0024ffc19e kernel/trace/blktrace.c Jens Axboe               2017-11-05  1617  	put_probe_ref();
c780e86dd48ef6 kernel/trace/blktrace.c Jan Kara                 2020-02-06  1618  	synchronize_rcu();
ad5dd5493a55e4 kernel/trace/blktrace.c Li Zefan                 2009-03-27  1619  	blk_trace_free(bt);
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1620  	return 0;
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1621  }
c71a896154119f block/blktrace.c        Arnaldo Carvalho de Melo 2009-01-23  1622  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 1183c88634aa..e900dd3efcbe 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -34,7 +34,7 @@  static struct trace_array *blk_tr;
 static bool blk_tracer_enabled __read_mostly;
 
 static LIST_HEAD(running_trace_list);
-static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
+static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
 
 /* Select an alternative, minimalistic output than the original one */
 #define TRACE_BLK_OPT_CLASSIC	0x1
@@ -121,12 +121,12 @@  static void trace_note_tsk(struct task_struct *tsk)
 	struct blk_trace *bt;
 
 	tsk->btrace_seq = blktrace_seq;
-	spin_lock_irqsave(&running_trace_lock, flags);
+	raw_spin_lock_irqsave(&running_trace_lock, flags);
 	list_for_each_entry(bt, &running_trace_list, running_list) {
 		trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
 			   sizeof(tsk->comm), 0);
 	}
-	spin_unlock_irqrestore(&running_trace_lock, flags);
+	raw_spin_unlock_irqrestore(&running_trace_lock, flags);
 }
 
 static void trace_note_time(struct blk_trace *bt)
@@ -666,9 +666,9 @@  static int __blk_trace_startstop(struct request_queue *q, int start)
 			blktrace_seq++;
 			smp_mb();
 			bt->trace_state = Blktrace_running;
-			spin_lock_irq(&running_trace_lock);
+			raw_spin_lock_irq(&running_trace_lock);
 			list_add(&bt->running_list, &running_trace_list);
-			spin_unlock_irq(&running_trace_lock);
+			raw_spin_unlock_irq(&running_trace_lock);
 
 			trace_note_time(bt);
 			ret = 0;
@@ -676,9 +676,9 @@  static int __blk_trace_startstop(struct request_queue *q, int start)
 	} else {
 		if (bt->trace_state == Blktrace_running) {
 			bt->trace_state = Blktrace_stopped;
-			spin_lock_irq(&running_trace_lock);
+			raw_spin_lock_irq(&running_trace_lock);
 			list_del_init(&bt->running_list);
-			spin_unlock_irq(&running_trace_lock);
+			raw_spin_unlock_irq(&running_trace_lock);
 			relay_flush(bt->rchan);
 			ret = 0;
 		}