On Thu, Jul 30, 2015 at 8:19 PM, Mike Snitzer <snit...@redhat.com> wrote: > On Thu, Jul 30 2015 at 7:14pm -0400, > Josh Boyer <jwbo...@fedoraproject.org> wrote: > >> On Thu, Jul 30, 2015 at 7:27 AM, Josh Boyer <jwbo...@fedoraproject.org> >> wrote: >> > On Wed, Jul 29, 2015 at 8:29 PM, Ming Lei <ming....@canonical.com> wrote: >> >> On Wed, Jul 29, 2015 at 12:36 PM, Josh Boyer <jwbo...@fedoraproject.org> >> >> wrote: >> >>> On Wed, Jul 29, 2015 at 11:32 AM, Ming Lei <ming....@canonical.com> >> >>> wrote: >> >>>> On Wed, Jul 29, 2015 at 9:51 AM, Johannes Weiner <han...@cmpxchg.org> >> >>>> wrote: >> >>>>> On Wed, Jul 29, 2015 at 09:27:16AM -0400, Josh Boyer wrote: >> >>>>>> Hi All, >> >>>>>> >> >>>>>> We've gotten a report[1] that any of the upcoming Fedora 23 install >> >>>>>> images are all failing on 32-bit VMs/machines. Looking at the first >> >>>>>> instance of the oops, it seems to be a bad page state where a page is >> >>>>>> still charged to a group and it is trying to be freed. The oops >> >>>>>> output is below. >> >>>>>> >> >>>>>> Has anyone seen this in their 32-bit testing at all? Thus far nobody >> >>>>>> can recreate this on a 64-bit machine/VM. >> >>>>>> >> >>>>>> josh >> >>>>>> >> >>>>>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1247382 >> >>>>>> >> >>>>>> [ 9.026738] systemd[1]: Switching root. >> >>>>>> [ 9.036467] systemd-journald[149]: Received SIGTERM from PID 1 >> >>>>>> (systemd). >> >>>>>> [ 9.082262] BUG: Bad page state in process kworker/u5:1 pfn:372ac >> >>>>>> [ 9.083989] page:f3d32ae0 count:0 mapcount:0 mapping:f2252178 >> >>>>>> index:0x16a >> >>>>>> [ 9.085755] flags: 0x40020021(locked|lru|mappedtodisk) >> >>>>>> [ 9.087284] page dumped because: page still charged to cgroup >> >>>>>> [ 9.088772] bad because of flags: >> >>>>>> [ 9.089731] flags: 0x21(locked|lru) >> >>>>>> [ 9.090818] page->mem_cgroup:f2c3e400 >> >>>>> >> >>>>> It's also still locked and on the LRU. This page shouldn't have been >> >>>>> freed. >> >>>>> >> >>>>>> [ 9.117848] Call Trace: >> >>>>>> [ 9.118738] [<c0aa22c9>] dump_stack+0x41/0x52 >> >>>>>> [ 9.120034] [<c054e30a>] bad_page.part.80+0xaa/0x100 >> >>>>>> [ 9.121461] [<c054eea9>] free_pages_prepare+0x3b9/0x3f0 >> >>>>>> [ 9.122934] [<c054fae2>] free_hot_cold_page+0x22/0x160 >> >>>>>> [ 9.124400] [<c071a22f>] ? copy_to_iter+0x1af/0x2a0 >> >>>>>> [ 9.125750] [<c054c4a3>] ? mempool_free_slab+0x13/0x20 >> >>>>>> [ 9.126840] [<c054fc57>] __free_pages+0x37/0x50 >> >>>>>> [ 9.127849] [<c054c4fd>] mempool_free_pages+0xd/0x10 >> >>>>>> [ 9.128908] [<c054c8b6>] mempool_free+0x26/0x80 >> >>>>>> [ 9.129895] [<c06f77e6>] bounce_end_io+0x56/0x80 >> >>>>> >> >>>>> The page state looks completely off for a bounce buffer page. Did >> >>>>> somebody mess with a bounce bio's bv_page? >> >>>> >> >>>> Looks the page isn't touched in both lo_read_transfer() and >> >>>> lo_read_simple(). >> >>>> >> >>>> Maybe it is related with aa4d86163e4e(block: loop: switch to VFS >> >>>> ITER_BVEC), >> >>>> or it might be helpful to run 'git bisect' if reverting aa4d86163e4e >> >>>> can't >> >>>> fix the issue, suppose the issue can be reproduced easily. >> >>> >> >>> I can try reverting that and getting someone to test it. It is >> >>> somewhat complicated by having to spin a new install ISO, so a report >> >>> back will be somewhat delayed. In the meantime, I'm also asking >> >>> people to track down the first kernel build that hits this, so >> >>> hopefully that gives us more of a clue as well. >> >> The revert of that patch did not fix the issue. >> >> >>> It is odd that only 32-bit hits this issue though. At least from what >> >>> we've seen thus far. >> >> >> >> Page bounce may be just valid on 32-bit, and I will try to find one ARM >> >> box to see if it can be reproduced easily. >> >> >> >> BTW, are there any extra steps for reproducing the issue? Such as >> >> cgroup operations? >> > >> > I'm not entirely sure what the install environment on the ISOs is >> > doing, but nobody sees this issue with a kernel after install. Thus >> > far recreate efforts have focused on recreating the install ISOs using >> > various kernels. That is working, but I don't expect other people to >> > easily be able to do that. >> > >> > Also, our primary tester seems to have narrowed it down to breaking >> > somewhere between 4.1-rc5 (good) and 4.1-rc6 (bad). I'll be working >> > with him today to isolate it further, but the commit you pointed out >> > was in 4.1-rc1 and that worked. He still needs to test a 4.2-rc4 >> > kernel with it reverted, but so far it seems to be something else that >> > came in with the 4.1 kernel. >> >> After doing some RPM bisecting, we've narrowed it down to the >> following commit range: >> >> [jwboyer@vader linux]$ git log --pretty=oneline c2102f3d73d8..0f1e5b5d19f6 >> 0f1e5b5d19f6c06fe2078f946377db9861f3910d Merge tag 'dm-4.1-fixes-3' of >> git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm >> 1c220c69ce0dcc0f234a9f263ad9c0864f971852 dm: fix casting bug in >> dm_merge_bvec() >> 15b94a690470038aa08247eedbebbe7e2218d5ee dm: fix reload failure of 0 >> path multipath mapping on blk-mq devices >> e5d8de32cc02a259e1a237ab57cba00f2930fa6a dm: fix false warning in >> free_rq_clone() for unmapped requests >> 45714fbed4556149d7f1730f5bae74f81d5e2cd5 dm: requeue from blk-mq >> dm_mq_queue_rq() using BLK_MQ_RQ_QUEUE_BUSY >> 4c6dd53dd3674c310d7379c6b3273daa9fd95c79 dm mpath: fix leak of >> dm_mpath_io structure in blk-mq .queue_rq error path >> 3a1407559a593d4360af12dd2df5296bf8eb0d28 dm: fix NULL pointer when >> clone_and_map_rq returns !DM_MAPIO_REMAPPED >> 4ae9944d132b160d444fa3aa875307eb0fa3eeec dm: run queue on re-queue >> [jwboyer@vader linux]$ >> >> It is interesting to note that we're also carrying a patch in our 4.1 >> kernel for loop performance reasons that went into upstream 4.2. That >> patch is blk-loop-avoid-too-many-pending-per-work-IO.patch which >> corresponds to upstream commit >> 4d4e41aef9429872ea3b105e83426941f7185ab6. All of those commits are in >> 4.2-rcX, which matches the failures we're seeing. >> >> We can try a 4.1-rc5 snapshot build without the block patch to see if >> that helps, but the patch was included in all the previously tested >> good kernels and the issue only appeared after the DM merge commits >> were included. > > The only commit that looks even remotely related (given 32bit concerns) > would be 1c220c69ce0dcc0f234a9f263ad9c0864f971852
Confirmed. I built kernels for our tester that started with the working snapshot and applied the patches above one at a time. The failing patch was the commit you suspected. I can try and build a 4.2-rc4 kernel with that reverted, but it would be good if someone could start thinking about how that could cause this issue. josh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
