Skip to content

L
linux
Switch branch/tag
  1. 24 Oct, 2018 6 commits
  3. 16 Oct, 2018 1 commit
  5. 09 Oct, 2018 1 commit
  7. 07 Oct, 2018 12 commits
  9. 05 Oct, 2018 1 commit
  11. 02 Oct, 2018 2 commits
  13. 18 Sep, 2018 2 commits
    • Waiman Long's avatar
      driver/dma/ioat: Call del_timer_sync() without holding prep_lock · cfb03be6
      Waiman Long authored 
      The following lockdep splat was observed:

[ 1222.241750] ======================================================
[ 1222.271301] WARNING: possible circular locking dependency detected
[ 1222.301060] 4.16.0-10.el8+5.x86_64+debug #1 Not tainted
[ 1222.326659] ------------------------------------------------------
[ 1222.356565] systemd-shutdow/1 is trying to acquire lock:
[ 1222.382660]  ((&ioat_chan->timer)){+.-.}, at: [<00000000f71e1a28>] del_timer_sync+0x5/0xf0
[ 1222.422928]
[ 1222.422928] but task is already holding lock:
[ 1222.451743]  (&(&ioat_chan->prep_lock)->rlock){+.-.}, at: [<000000008ea98b12>] ioat_shutdown+0x86/0x100 [ioatdma]
   :
[ 1223.524987] Chain exists of:
[ 1223.524987]   (&ioat_chan->timer) --> &(&ioat_chan->cleanup_lock)->rlock --> &(&ioat_chan->prep_lock)->rlock
[ 1223.524987]
[ 1223.594082]  Possible unsafe locking scenario:
[ 1223.594082]
[ 1223.622630]        CPU0                    CPU1
[ 1223.645080]        ----                    ----
[ 1223.667404]   lock(&(&ioat_chan->prep_lock)->rlock);
[ 1223.691535]                                lock(&(&ioat_chan->cleanup_lock)->rlock);
[ 1223.728657]                                lock(&(&ioat_chan->prep_lock)->rlock);
[ 1223.765122]   lock((&ioat_chan->timer));
[ 1223.784095]
[ 1223.784095]  *** DEADLOCK ***
[ 1223.784095]
[ 1223.813492] 4 locks held by systemd-shutdow/1:
[ 1223.834677]  #0:  (reboot_mutex){+.+.}, at: [<0000000056d33456>] SYSC_reboot+0x10f/0x300
[ 1223.873310]  #1:  (&dev->mutex){....}, at: [<00000000258dfdd7>] device_shutdown+0x1c8/0x660
[ 1223.913604]  #2:  (&dev->mutex){....}, at: [<0000000068331147>] device_shutdown+0x1d6/0x660
[ 1223.954000]  #3:  (&(&ioat_chan->prep_lock)->rlock){+.-.}, at: [<000000008ea98b12>] ioat_shutdown+0x86/0x100 [ioatdma]

In the ioat_shutdown() function:

	spin_lock_bh(&ioat_chan->prep_lock);
	set_bit(IOAT_CHAN_DOWN, &ioat_chan->state);
	del_timer_sync(&ioat_chan->timer);
	spin_unlock_bh(&ioat_chan->prep_lock);

According to the synchronization rule for the del_timer_sync() function,
the caller must not hold locks which would prevent completion of the
timer's handler.

The timer structure has its own lock that manages its synchronization.
Setting the IOAT_CHAN_DOWN bit should prevent other CPUs from
trying to use that device anyway, there is probably no need to call
del_timer_sync() while holding the prep_lock. So the del_timer_sync()
call is now moved outside of the prep_lock critical section to prevent
the circular lock dependency.
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Reviewed-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
      cfb03be6
    • Angelo Dureghello's avatar
      dmaengine: mcf-edma: avoid warning for wrong pointer cast · 5b7d0c94
      Angelo Dureghello authored 
      This patch fixes the following compilation warning
reported during x86_64 allmodconfig build:

  drivers/dma/mcf-edma.c: In function 'mcf_edma_filter_fn':
  drivers/dma/mcf-edma.c:296:33: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
        return (mcf_chan->slave_id == (u32)param);
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarAngelo Dureghello <angelo@sysam.it>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
      5b7d0c94
  15. 11 Sep, 2018 7 commits
  17. 03 Sep, 2018 2 commits
  19. 29 Aug, 2018 6 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7