From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1421705231.31046.191.camel@decadent.org.uk> Subject: Re: [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx From: Ben Hutchings To: Steven Rostedt Cc: LKML , stable , Yinghai Lu , "H. Peter Anvin" Date: Mon, 19 Jan 2015 22:07:11 +0000 In-Reply-To: <20150119164926.168e8101@gandalf.local.home> References: <20150119164926.168e8101@gandalf.local.home> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-dJ7YrZOmZ6FwwijFklr7" Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: --=-dJ7YrZOmZ6FwwijFklr7 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2015-01-19 at 16:49 -0500, Steven Rostedt wrote: > Testing v3.2-rt I found that after merging the latest v3.2 stable tree, > hotplug stopped working. I tested the latest v3.2 stable, and it was > not working there either. I bisected it down to: >=20 > commit e105c8187b7101e8a8a54ac0218c9d9c9463c636 > Author: Yinghai Lu > Date: Thu Jan 24 12:20:13 2013 -0800 >=20 > x86, 64bit, mm: Mark data/bss/brk to nx > =20 > commit 72212675d1c96f5db8ec6fb35701879911193158 upstream. >=20 > Simply doing: >=20 > # echo 0 > /sys/devices/system/cpu/cpu1/online > # echo 1 > /sys/devices/system/cpu/cpu1/online >=20 > caused the system to reboot. >=20 > After reverting that commit, hotplug works again on the v3.2 stable > tree. Yes, I know this needs fixing. It also broke suspend/resume on SMP machines since that involves offlining and onlining CPUs 1-n. Ben. > Signed-off-by: Steven Rostedt > --- > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 266f71719e42..783eba48d00c 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -778,7 +778,6 @@ void mark_rodata_ro(void) > unsigned long text_end =3D PAGE_ALIGN((unsigned long) &__stop___ex_tabl= e); > unsigned long rodata_end =3D PAGE_ALIGN((unsigned long) &__end_rodata); > unsigned long data_start =3D (unsigned long) &_sdata; > - unsigned long all_end; > =20 > printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", > (end - start) >> 10); > @@ -787,8 +786,8 @@ void mark_rodata_ro(void) > kernel_set_to_readonly =3D 1; > =20 > /* > - * The rodata/data/bss/brk section (but not the kernel text!) > - * should also be not-executable. > + * The rodata section (but not the kernel text!) should also be > + * not-executable. > * > * We align all_end to PMD_SIZE because the existing mapping > * is a full PMD. If we would align _brk_end to PAGE_SIZE we > @@ -798,8 +797,7 @@ void mark_rodata_ro(void) > * Any PMD which was setup after the one which covers _brk_end > * has been zapped already via cleanup_highmem(). > */ > - all_end =3D roundup((unsigned long)_brk_end, PMD_SIZE); > - set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT); > + set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT); > =20 > rodata_test(); > =20 --=20 Ben Hutchings Larkinson's Law: All laws are basically false. --=-dJ7YrZOmZ6FwwijFklr7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIVAwUAVL2AFOe/yOyVhhEJAQqsMg//Y3bwMnEuiwf5JC52NmWjVIChniQ9NWA7 S+AWbT2I9rJHpuo9ppdRIEMvcFHfcaDQY1icHwFp6A6PNgJNSfZbE4yuEXD+J3sd /DV6q9yxA5GNXbNX+iOa8SK6qD+O5S2O3VWOLWIle3W7ZB0g+WUIB0ulIjVL+l5F jPUTulCRnB7L4jq5oO74VkbAGKuu1Qo5e620m/mcaVAXXaBrC0BwafDtwCOpJPdx YTogLAYY1l0fIN/0j9gE4NzP2YxbCBs4SAfosCGOEhl8SG2pTl2UsLaN5YiypKYa t5r8Id83QPl65ZBfGflmSt+fg/6sGSSwJTY79X2AfxFgUwLsQJ5NUsDnZaCapNe4 P6VcGQPNqNFhqT4EqZn399KxmzWJlrV4ydD2EZQCZS+ZkwA3ODVOpIZZUlJxTQIl Adqpn6VXBqwsUIiB2b8Ng8cX2srADPqm6YvaSv/BLXDqS3MNYV64+gF2HHxImTGp 82/yZWM+gFgiLa31IUervCOn3FQnfI78UFd4W5iKNTEA2kp+peoUzqAI/gvYSCI/ n9kjnc1+VUBraXblWcRMbmBmDCNq21gichFnNdRoDG0MtgCesyLWImqtyYEqt3/X gVCi1YLEoxhoYO6go5H18TJVRypVzdDQpgB9Uk2FLqsBUw+8zBSUwP1loG3bDGYn ZAuDWsAjnXs= =Ajfa -----END PGP SIGNATURE----- --=-dJ7YrZOmZ6FwwijFklr7--