Messages in this thread Patch in this message | | | Date | Fri, 4 Jul 2008 21:29:13 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: Lockless/Get_User_Pages_Fast causes Xorg 1.4.99.* to lock |
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On Fri, 4 Jul 2008, Zan Lynx wrote: > Ryan Hope wrote: > > I have tested this with 2.6.26-rc5-mm3 and with 2.6.26-rc8 w/ the > > get_user_pages_fast patches from -rc5-mm3... Xorg 1.4.99.* will start > > to load but hangs at a black screen. At this point, I can not switch > > to another tty. When I try pressing ctrl+alt+del the kernel ooopses > > and the caps lock led starts to blink. This happens using the nv, > > radeon and radeonhd drivers (the nv was tested on another box > > obviously). I have also tried to unselect HAVE_GET_USER_PAGES_FAST in > > my kernel config but this does not help. I can not figure out where or > > what the bug is. I can provide any other info you guys need to figure > > this out. Let me know what I can do. > > I think that I've seen this too on 2.6.26-rc8 on my laptop. It's 64-bit
Your attachment tells us it's actually 2.6.26-rc8-mm1, less of a worry.
> AMD-64 single core (although I run a SMP-alternatives kernel on it) and I was > using the nv driver. > > The symptoms are the same. Everything was working great until I started X. I > SSH'd in and got the dmesg after X locked up. The full dmesg and config are > attached because Thunderbird is a very stupid program and won't let me paste > without wrapping. > > Here is a bit of what I got though. > > [ 269.224276] BUG: unable to handle kernel paging request at ffffe20003480000 > [ 269.224291] IP: [<ffffffff80297e30>] copy_page_range+0x520/0x760 > [ 269.224306] PGD 1102067 PUD 1103067 PMD 0 > [ 269.224315] Oops: 0000 [1] SMP > > [ 269.224473] Call Trace: > [ 269.224495] [<ffffffff80239a9b>] dup_mm+0x26b/0x3c0 > [ 269.224507] [<ffffffff8023a84c>] copy_process+0xc2c/0x1210 > [ 269.224518] [<ffffffff8023aea3>] do_fork+0x73/0x310 > [ 269.224526] [<ffffffff8024719e>] sys_rt_sigaction+0x8e/0xd0 > [ 269.224536] [<ffffffff8020c2db>] system_call_after_swapgs+0x7b/0x80 > [ 269.224542] [<ffffffff8020c5d7>] ptregscall_common+0x67/0xb0
Useful info, thank you; even more useful was the Code line in your attachment
> [ 269.224557] Code: 00 00 48 b9 00 00 00 00 00 e2 ff ff 48 21 d8 48 c1 e8 0c 48 8d 14 c5 00 00 00 00 48 c1 e0 06 48 29 d0 48 01 c1 0f 84 10 ff ff ff <48> 8b 01 48 89 ca f6 c4 40 74 04 48 8b 51 10 90 ff 42 08 90 ff
which is enough to identify the oops as in copy_one_pte's get_page(page). Here's a patch I think we need, which I'm hoping will fix both your crashes - please let us know - thanks a lot.
Stop mprotect's pte_modify from wiping out the x86 pte_special bit, which caused oops thereafter when vm_normal_page thought X's abnormal was normal.
Signed-off-by: Hugh Dickins <hugh@veritas.com> --- Fix to 2.6.26-rc8-mm1 x86-implement-pte_special.patch Perhaps something similar needed for powerpc? Nick will know.
include/asm-x86/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 2.6.26-rc8-mm1/include/asm-x86/pgtable.h 2008-07-03 11:34:55.000000000 +0100 +++ linux/include/asm-x86/pgtable.h 2008-07-04 20:58:36.000000000 +0100 @@ -57,7 +57,7 @@ /* Set of bits not changed in pte_modify */ #define _PAGE_CHG_MASK (PTE_MASK | _PAGE_PCD | _PAGE_PWT | \ - _PAGE_ACCESSED | _PAGE_DIRTY) + _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY) #define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT) #define _PAGE_CACHE_WB (0)
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