[Kernel GRSecurity] Error on boot

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[Kernel GRSecurity] Error on boot

Postby Qwaser » Thu Feb 23, 2017 5:40 pm

Hello,

After a new installation of Archlinux on my server, I can't boot. I have this message : [1.268333] PAX: size overflow detected in function read_sb_page drivers / md / bitmap.c: 161 cicus.372_45 min, count: 4, decl: sync_page_io; Num: 2; Context: fndecl;

Archlinux was installed in UEFI mode with RAID 1 of two 2TB hard disks and BTRFS file system. On a virtual machine reproducing my server identically, except the size of the disk, I don't have this error. Would that be related to my hard disks ?

Do you have an idea ?

Thank you in advance for your help !

Qwaser

PS : I am young French, sorry in advance for my English.
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Re: [Kernel GRSecurity] Error on boot

Postby PaX Team » Thu Feb 23, 2017 5:58 pm

which kernel/grsec is this? also the full log (including the backtrace) would be useful.
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Re: [Kernel GRSecurity] Error on boot

Postby Qwaser » Thu Feb 23, 2017 6:12 pm

This is kernel 4.9.11-201702222257 as shown here: https://www.archlinux.org/packages/comm ... inux-grsec

How to get the full log with the backtrace ? :/
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Re: [Kernel GRSecurity] Error on boot

Postby spender » Thu Feb 23, 2017 6:55 pm

You can boot the system with "pax_size_overflow_report_only" on the kernel commandline.

-Brad
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Re: [Kernel GRSecurity] Error on boot

Postby ephox » Thu Feb 23, 2017 7:05 pm

Hi,

Could you please apply this patch and send me the result from dmesg?
Code: Select all
--- drivers/md/bitmap.c.orig    2017-02-24 00:00:03.922434066 +0100
+++ drivers/md/bitmap.c 2017-02-24 00:01:04.950434888 +0100
@@ -158,6 +158,7 @@
                    || test_bit(Faulty, &rdev->flags))
                        continue;
 
+               printk(KERN_ERR "PAX: offset: %llx, index: %lx\n", offset, index);
                target = offset + index * (PAGE_SIZE/512);
 
                if (sync_page_io(rdev, target,
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Re: [Kernel GRSecurity] Error on boot

Postby Qwaser » Fri Feb 24, 2017 6:26 pm

I try to reinstall Archlinux on my server, and this time I get to boot ! :o
But the PAX error is always present. With the "pax_size_overflow_report_only" on the kernel commandline, here are the errors :

[ 1.227593] PAX: size overflow detected in function read_sb_page drivers/md/bitmap.c:161 cicus.372_45 min, count: 4, decl: sync_page_io; num: 2; context: fndecl;
[ 1.227690] PAX: size overflow detected in function sync_page_io drivers/md/md.c:768 cicus.1727_86 max, count: 187, decl: bi_sector; num: 0; context: bvec_iter;
[ 1.227922] PAX: size overflow detected in function read_sb_page drivers/md/bitmap.c:161 cicus.372_45 min, count: 4, decl: sync_page_io; num: 2; context: fndecl;

What do these errors mean ? For if I can get booted is that it should not be of a critical level ?

@ephox : How do I apply the patch ?
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