Thank you for your replies! Actually I don't see anything that makes me suspect zram as the culprit. I mentioned it just in case you folks knew of any bug that would result in that behavior. Thank you for the suggestion to backport---I'll look into it. Of course I would prefer to backport code that I actually know fixes this mm problem. On Wed, Apr 15, 2015 at 1:22 AM, Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> wrote: > On (04/15/15 16:16), Minchan Kim wrote: >> On Tue, Apr 14, 2015 at 11:36:57AM -0700, Luigi Semenzato wrote: >> > We are seeing several instances of these things (often with different >> > but plausible values in the struct page) in kernel 3.8.11, followed by >> > a panic() in release_pages a few seconds later. >> > >> > I realize it's an old kernel and probably of little interest here, but >> > I would be most grateful for any pointers on how to proceed. In >> > particular, I suspect that many such bugs may have been fixed by now, >> > but I am not sure how to find the right fix (which I would backport). >> > >> > Also, this happens under heavy swap, and we're using zram. I wonder >> > if there may be a race condition related to zram which may have been >> > fixed since then, and which may result in these symptoms. >> >> I didn't see such bug until now. Sorry. However, I might miss something >> because zram has changed a lot since then. >> What I recommend is just to use recent zram/zsmalloc. >> I think it's not hard to backport it because they are almost isolated >> from other parts in kernel. >> If you don't see any problem any more with recent zram, yay, your >> system doesn't have any problem. But if you see the problem still, >> it means you should suspect another stuffs as culprits as well as >> zram. >> >> Thanks. >> > > assuming that you use zram0, does 'mkswap -c /dev/zram0' show any bad > pages right after the swap creation/activation? > > -ss > >> > <1>[ 5392.106074] BUG: Bad page state in process CompositorTileW pfn:57a7e >> > <1>[ 5392.106109] page:ffffea00015e9f80 count:0 mapcount:0 mapping: >> > (null) index:0x2 >> > <1>[ 5392.106122] page flags: 0x4000000000000004(referenced) >> > <5>[ 5392.106139] Modules linked in: i2c_dev uinput >> > snd_hda_codec_realtek memconsole snd_hda_codec_hdmi uvcvideo >> > videobuf2_vmalloc videobuf2_memops videobuf2_core videodev >> > snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_timer >> > zram(C) lzo_compress zsmalloc(C) fuse nf_conntrack_ipv6 nf_defrag_ipv6 >> > ip6table_filter ip6_tables ath9k_btcoex ath9k_common_btcoex >> > ath9k_hw_btcoex ath mac80211 cfg80211 option usb_wwan cdc_ether usbnet >> > ath3k btusb bluetooth joydev ppp_async ppp_generic slhc tun >> > <5>[ 5392.106333] Pid: 27363, comm: CompositorTileW Tainted: G B >> > C 3.8.11 #1 >> > <5>[ 5392.106344] Call Trace: >> > <5>[ 5392.106357] [<ffffffff978ba5bb>] bad_page+0xcf/0xe3 >> > <5>[ 5392.106370] [<ffffffff978bb181>] get_page_from_freelist+0x21a/0x46c >> > <5>[ 5392.106383] [<ffffffff978beb74>] ? release_pages+0x19b/0x1be >> > <5>[ 5392.106394] [<ffffffff978bb5da>] __alloc_pages_nodemask+0x207/0x685 >> > <5>[ 5392.106407] [<ffffffff97cb8caf>] ? _cond_resched+0xe/0x1e >> > <5>[ 5392.106421] [<ffffffff978d215a>] handle_pte_fault+0x305/0x500 >> > <5>[ 5392.106433] [<ffffffff978d4f5e>] ? __vma_link_file+0x65/0x67 >> > <5>[ 5392.106445] [<ffffffff978d30d0>] handle_mm_fault+0x97/0xbb >> > <5>[ 5392.106459] [<ffffffff97828616>] __do_page_fault+0x1d4/0x38c >> > <5>[ 5392.106470] [<ffffffff978d7803>] ? do_mmap_pgoff+0x284/0x2c0 >> > <5>[ 5392.106482] [<ffffffff978ca82c>] ? vm_mmap_pgoff+0x7d/0x8e >> > <5>[ 5392.106495] [<ffffffff97828800>] do_page_fault+0xe/0x10 >> > <5>[ 5392.106506] [<ffffffff97cb9d32>] page_fault+0x22/0x30 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>