On 2017/05/02 13:12, Marc MERLIN wrote: > Well, sadly, the problem is more or less back is 4.11.0. The system doesn't > really > crash but it goes into an infinite loop with > [34776.826800] BUG: workqueue lockup - pool cpus=6 node=0 flags=0x0 nice=0 > stuck for 33s!
Wow, two of workqueues are reaching max active. [34777.202267] workqueue btrfs-endio-write: flags=0xe [34777.218313] pwq 16: cpus=0-7 flags=0x4 nice=0 active=8/8 [34777.236548] in-flight: 15168:btrfs_endio_write_helper, 13855:btrfs_endio_write_helper, 3360:btrfs_endio_write_helper, 14241:btrfs_endio_write_helper, 27092:btrfs_endio_write_helper, 15194:btrfs_endio_write_helper, 15169:btrfs_endio_write_helper, 27093:btrfs_endio_write_helper [34777.316225] delayed: btrfs_endio_write_helper, btrfs_endio_write_helper, btrfs_endio_write_helper, btrfs_endio_write_helper, btrfs_endio_write_helper, btrfs_endio_write_helper [34777.450684] workqueue bcache: flags=0x8 [34779.956462] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=256/256 [34779.978283] in-flight: 15320:cached_dev_read_done [bcache], 23385:cached_dev_read_done [bcache], 23371:cached_dev_read_done [bcache], 15321:cached_dev_read_done [bcache], 15395:cached_dev_read_done [bcache], 11101:cached_dev_read_done [bcache], 15300:cached_dev_read_done [bcache], 23349:cached_dev_read_done [bcache], 23425:cached_dev_read_done [bcache], 23399:cached_dev_read_done [bcache], 15293:cached_dev_read_done [bcache], 20529:cached_dev_read_done [bcache], 15402:cached_dev_read_done [bcache], 23422:cached_dev_read_done [bcache], 23417:cached_dev_read_done [bcache], 23409:cached_dev_read_done [bcache], 20539:cached_dev_read_done [bcache], 23431:cached_dev_read_done [bcache], 20544:cached_dev_read_done [bcache], 15355:cached_dev_read_done [bcache], 11085:cached_dev_read_done [bcache], 6511:cached_dev_read_done [bcache] Googling with btrfs_endio_write_helper shows a stuck report with 4.8-rc5, but seems no response ( https://www.spinics.net/lists/linux-btrfs/msg58633.html ). > Any idea what I should do next? Maybe you can try collecting list of all in-flight allocations with backtraces using kmallocwd patches at http://lkml.kernel.org/r/1489578541-81526-1-git-send-email-penguin-ker...@i-love.sakura.ne.jp and http://lkml.kernel.org/r/201704272019.jeh26057.shfotmljoov...@i-love.sakura.ne.jp which also tracks mempool allocations. (Well, the - cond_resched(); + //cond_resched(); change in the latter patch would not be preferable.)
