On Wed, Feb 19, 2020 at 08:26:52AM +1100, Dave Chinner wrote: > On Tue, Feb 18, 2020 at 05:42:30AM -0800, Matthew Wilcox wrote: > > On Tue, Feb 18, 2020 at 03:56:33PM +1100, Dave Chinner wrote: > > > Latest version in your git tree: > > > > > > $ ▶ glo -n 5 willy/readahead > > > 4be497096c04 mm: Use memalloc_nofs_save in readahead path > > > ff63497fcb98 iomap: Convert from readpages to readahead > > > 26aee60e89b5 iomap: Restructure iomap_readpages_actor > > > 8115bcca7312 fuse: Convert from readpages to readahead > > > 3db3d10d9ea1 f2fs: Convert from readpages to readahead > > > $ > > > > > > merged into a 5.6-rc2 tree fails at boot on my test vm: > > > > > > [ 2.423116] ------------[ cut here ]------------ > > > [ 2.424957] list_add double add: new=ffffea000efff4c8, prev=ffff8883bfffee60, next=ffffea000efff4c8. > > > [ 2.428259] WARNING: CPU: 4 PID: 1 at lib/list_debug.c:29 __list_add_valid+0x67/0x70 > > > [ 2.457484] Call Trace: > > > [ 2.458171] __pagevec_lru_add_fn+0x15f/0x2c0 > > > [ 2.459376] pagevec_lru_move_fn+0x87/0xd0 > > > [ 2.460500] ? pagevec_move_tail_fn+0x2d0/0x2d0 > > > [ 2.461712] lru_add_drain_cpu+0x8d/0x160 > > > [ 2.462787] lru_add_drain+0x18/0x20 > > > > Are you sure that was 4be497096c04 ? I ask because there was a > > Yes, because it's the only version I've actually merged into my > working tree, compiled and tried to run. :P > > > version pushed to that git tree that did contain a list double-add > > (due to a mismerge when shuffling patches). I noticed it and fixed > > it, and 4be497096c04 doesn't have that problem. I also test with > > CONFIG_DEBUG_LIST turned on, but this problem you hit is going to be > > probabilistic because it'll depend on the timing between whatever other > > list is being used and the page actually being added to the LRU. > > I'll see if I can reproduce it. Just updated to a current TOT Linus kernel and your latest branch, and so far this is 100% reproducable. Not sure how I'm going to debug it yet, because it's init that is triggering it.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
