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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-10 09:05:52 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-10 09:05:52 -0800 |
commit | af5feae3d7e821d8c4d38103a7f53146f2590892 (patch) | |
tree | 9017bb0661fb617177534f0617c3771d89e31afc /mm | |
parent | ce2814f227d3adae8456f7cbd0bd5f922fd284f0 (diff) | |
parent | 977b7e3a52a7421ad33a393a38ece59f3d41c2fa (diff) | |
download | linux-af5feae3d7e821d8c4d38103a7f53146f2590892.tar.gz linux-af5feae3d7e821d8c4d38103a7f53146f2590892.tar.bz2 linux-af5feae3d7e821d8c4d38103a7f53146f2590892.zip |
Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
fix 1 mysterious divide error
fix 3 NULL dereference bugs in writeback tracing, on SD card removal w/o umount
* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue
lib: proportion: lower PROP_MAX_SHIFT to 32 on 64-bit kernel
writeback: fix NULL bdi->dev in trace writeback_single_inode
backing-dev: fix wakeup timer races with bdi_unregister()
Diffstat (limited to 'mm')
-rw-r--r-- | mm/backing-dev.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 7ba8feae11b8..dd8e2aafb07e 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -318,7 +318,7 @@ static void wakeup_timer_fn(unsigned long data) if (bdi->wb.task) { trace_writeback_wake_thread(bdi); wake_up_process(bdi->wb.task); - } else { + } else if (bdi->dev) { /* * When bdi tasks are inactive for long time, they are killed. * In this case we have to wake-up the forker thread which @@ -584,6 +584,8 @@ EXPORT_SYMBOL(bdi_register_dev); */ static void bdi_wb_shutdown(struct backing_dev_info *bdi) { + struct task_struct *task; + if (!bdi_cap_writeback_dirty(bdi)) return; @@ -602,8 +604,13 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) * Finally, kill the kernel thread. We don't need to be RCU * safe anymore, since the bdi is gone from visibility. */ - if (bdi->wb.task) - kthread_stop(bdi->wb.task); + spin_lock_bh(&bdi->wb_lock); + task = bdi->wb.task; + bdi->wb.task = NULL; + spin_unlock_bh(&bdi->wb_lock); + + if (task) + kthread_stop(task); } /* @@ -623,7 +630,9 @@ static void bdi_prune_sb(struct backing_dev_info *bdi) void bdi_unregister(struct backing_dev_info *bdi) { - if (bdi->dev) { + struct device *dev = bdi->dev; + + if (dev) { bdi_set_min_ratio(bdi, 0); trace_writeback_bdi_unregister(bdi); bdi_prune_sb(bdi); @@ -632,8 +641,12 @@ void bdi_unregister(struct backing_dev_info *bdi) if (!bdi_cap_flush_forker(bdi)) bdi_wb_shutdown(bdi); bdi_debug_unregister(bdi); - device_unregister(bdi->dev); + + spin_lock_bh(&bdi->wb_lock); bdi->dev = NULL; + spin_unlock_bh(&bdi->wb_lock); + + device_unregister(dev); } } EXPORT_SYMBOL(bdi_unregister); |