Messages in this thread Patch in this message | | | Date | Mon, 30 Jul 2012 15:11:27 -0400 | From | Larry Woodman <> | Subject | Re: [PATCH -alternative] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables V2 (resend) |
| |
On 07/27/2012 06:23 AM, Mel Gorman wrote: > On Thu, Jul 26, 2012 at 11:48:56PM -0400, Larry Woodman wrote: >> On 07/26/2012 02:37 PM, Rik van Riel wrote: >>> On 07/23/2012 12:04 AM, Hugh Dickins wrote: >>> >>>> I spent hours trying to dream up a better patch, trying various >>>> approaches. I think I have a nice one now, what do you think? And >>>> more importantly, does it work? I have not tried to test it at all, >>>> that I'm hoping to leave to you, I'm sure you'll attack it with gusto! >>>> >>>> If you like it, please take it over and add your comments and signoff >>>> and send it in. The second part won't come up in your testing, >>>> and could >>>> be made a separate patch if you prefer: it's a related point that struck >>>> me while I was playing with a different approach. >>>> >>>> I'm sorely tempted to leave a dangerous pair of eyes off the Cc, >>>> but that too would be unfair. >>>> >>>> Subject-to-your-testing- >>>> Signed-off-by: Hugh Dickins<hughd@google.com> >>> This patch looks good to me. >>> >>> Larry, does Hugh's patch survive your testing? >>> >>> >> Like I said earlier, no. > That is a surprise. Can you try your test case on 3.4 and tell us if the > patch fixes the problem there? I would like to rule out the possibility > that the locking rules are slightly different in RHEL. If it hits on 3.4 > then it's also possible you are seeing a different bug, more on this later. >
Sorry for the delay Mel, here is the BUG() traceback from the 3.4 kernel with your patches:
-------------------------------------------------------------------------------------------------------------------------------------------- [ 1106.156569] ------------[ cut here ]------------ [ 1106.161731] kernel BUG at mm/filemap.c:135! [ 1106.166395] invalid opcode: 0000 [#1] SMP [ 1106.170975] CPU 22 [ 1106.173115] Modules linked in: bridge stp llc sunrpc binfmt_misc dcdbas microcode pcspkr acpi_pad acpi] [ 1106.201770] [ 1106.203426] Pid: 18001, comm: mpitest Tainted: G W 3.3.0+ #4 Dell Inc. PowerEdge R620/07NDJ2 [ 1106.213822] RIP: 0010:[<ffffffff8112cfed>] [<ffffffff8112cfed>] __delete_from_page_cache+0x15d/0x170 [ 1106.224117] RSP: 0018:ffff880428973b88 EFLAGS: 00010002 [ 1106.230032] RAX: 0000000000000001 RBX: ffffea0006b80000 RCX: 00000000ffffffb0 [ 1106.237979] RDX: 0000000000016df1 RSI: 0000000000000009 RDI: ffff88043ffd9e00 [ 1106.245927] RBP: ffff880428973b98 R08: 0000000000000050 R09: 0000000000000003 [ 1106.253876] R10: 000000000000000d R11: 0000000000000000 R12: ffff880428708150 [ 1106.261826] R13: ffff880428708150 R14: 0000000000000000 R15: ffffea0006b80000 [ 1106.269780] FS: 0000000000000000(0000) GS:ffff88042fd60000(0000) knlGS:0000000000000000 [ 1106.278794] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1106.285193] CR2: 0000003a1d38c4a8 CR3: 000000000187d000 CR4: 00000000000406e0 [ 1106.293149] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1106.301097] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 1106.309046] Process mpitest (pid: 18001, threadinfo ffff880428972000, task ffff880428b5cc20) [ 1106.318447] Stack: [ 1106.320690] ffffea0006b80000 0000000000000000 ffff880428973bc8 ffffffff8112d040 [ 1106.328958] ffff880428973bc8 00000000000002ab 00000000000002a0 ffff880428973c18 [ 1106.337234] ffff880428973cc8 ffffffff8125b405 ffff880400000001 0000000000000000 [ 1106.345513] Call Trace: [ 1106.348235] [<ffffffff8112d040>] delete_from_page_cache+0x40/0x80 [ 1106.355128] [<ffffffff8125b405>] truncate_hugepages+0x115/0x1f0 [ 1106.361826] [<ffffffff8125b4f8>] hugetlbfs_evict_inode+0x18/0x30 [ 1106.368615] [<ffffffff811ab1af>] evict+0x9f/0x1b0 [ 1106.373951] [<ffffffff811ab3a3>] iput_final+0xe3/0x1e0 [ 1106.379773] [<ffffffff811ab4de>] iput+0x3e/0x50 [ 1106.384922] [<ffffffff811a8e18>] d_kill+0xf8/0x110 [ 1106.390356] [<ffffffff811a8f12>] dput+0xe2/0x1b0 [ 1106.395595] [<ffffffff81193612>] __fput+0x162/0x240 [ 1106.401124] [<ffffffff81193715>] fput+0x25/0x30 [ 1106.406265] [<ffffffff8118f6c3>] filp_close+0x63/0x90 [ 1106.411997] [<ffffffff8106058f>] put_files_struct+0x7f/0xf0 [ 1106.418302] [<ffffffff8106064c>] exit_files+0x4c/0x60 [ 1106.424025] [<ffffffff810629d7>] do_exit+0x1a7/0x470 [ 1106.429652] [<ffffffff81062cf5>] do_group_exit+0x55/0xd0 [ 1106.435665] [<ffffffff81062d87>] sys_exit_group+0x17/0x20 [ 1106.441777] [<ffffffff815d0229>] system_call_fastpath+0x16/0x1b [ 1106.448474] Code: 66 0f 1f 44 00 00 48 8b 47 08 48 8b 00 48 8b 40 28 44 8b 80 38 03 00 00 45 85 c0 0f [ 1106.470022] RIP [<ffffffff8112cfed>] __delete_from_page_cache+0x15d/0x170 [ 1106.477693] RSP <ffff880428973b88> --------------------------------------------------------------------------------------------------------------------------------------
I'll see if I can distribute the program that causes the panic, I dont have source, only binary.
Larry
BTW, the only way Ilve been able to get the panic to stop is:
-------------------------------------------------------------------------------------------------------------------------------------- diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c36febb..cc023b8 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2151,7 +2151,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, goto nomem;
/* If the pagetables are shared don't copy or take references */ - if (dst_pte == src_pte) + if (*(unsigned long *)dst_pte == *(unsigned long *)src_pte) continue; spin_lock(&dst->page_table_lock); ---------------------------------------------------------------------------------------------------------------------------------------
| |