Re: [PATCH] [26/31] CPA: Fix reference counting when changing already changed pages | KernelTrap

Re: [PATCH] [26/31] CPA: Fix reference counting when changing already changed pages

view
thread

!MAILaRCHIVE_VOTE_RePLACE

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

[view in full thread]

From: Jan Beulich <jbeulich@...>

To: Andi Kleen <ak@...>

Cc: <mingo@...>, <tglx@...>, <linux-kernel@...>

Subject: Re: [PATCH] [26/31] CPA: Fix reference counting when changing already changed pages

Date: Tuesday, January 15, 2008 - 8:00 am

>>> Andi Kleen <ak@suse.de> 15.01.08 11:04 >>>
quoted text>On Tuesday 15 January 2008 10:05:44 Jan Beulich wrote:
>> >+	ref_prot = canon_pgprot(ref_prot);
>> >+	prot = canon_pgprot(prot);
>> >+
>> > 	if (pgprot_val(prot) != pgprot_val(ref_prot)) { 
>> >...
>> > 	} else if (level == 4) {
>> >...
>> > 	} else {
>> > 		/*
>> > 		 * When you're here you either set the same page to PAGE_KERNEL
>> 
>> Doesn't this change require modifying the BUG() here into a BUG_ON() so
>> that it doesn't trigger if pgprot_val(prot) == pgprot_val(ref_prot) and
>> level != 4?
>
>I addressed this in the comment
>
>+               /*
>+                * When you're here you either set the same page to PAGE_KERNEL
>+                * two times in a row or the page table reference counting is
>+                * broken again. To catch the later bug for now (sorry)
>+                */
>
>Do you think it's important to handle?  The function already has too many
>special cases and setting something several times in a row to PAGE_KERNEL
>is usually a bug in the caller anyways (or a cpa bug)

It definitely is when making ref_prot variable (as discussed in an earlier
reply regarding a different patch), but I think it's even inconsistent given
the possible presence/absence of _PAGE_NX.

Jan

--
unsubscribe noticeTo unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

Messages in current thread:

[PATCH] [0/31] Great change_page_attr patch series v2, Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [0/31] Great change_page_attr patch series v2, Jan Beulich, (Tue Jan 15, 5:11 am)

Re: [PATCH] [0/31] Great change_page_attr patch series v2, Andi Kleen, (Tue Jan 15, 6:06 am)

Re: [PATCH] [0/31] Great change_page_attr patch series v2, Jan Beulich, (Tue Jan 15, 7:55 am)

Re: [PATCH] [0/31] Great change_page_attr patch series v2, Andi Kleen, (Tue Jan 15, 8:43 am)

[PATCH] [31/31] Clean up pte_exec, Andi Kleen, (Mon Jan 14, 6:17 pm)

[PATCH] [30/31] Remove set_kernel_exec, Andi Kleen, (Mon Jan 14, 6:17 pm)

[PATCH] [29/31] CPA: Add a BUG_ON checking for someone setti..., Andi Kleen, (Mon Jan 14, 6:17 pm)

[PATCH] [28/31] CPA: Make kernel_text test match boot mappin..., Andi Kleen, (Mon Jan 14, 6:17 pm)

[PATCH] [27/31] CPA: Change comments of external interfaces ..., Andi Kleen, (Mon Jan 14, 6:17 pm)

Re: [PATCH] [27/31] CPA: Change comments of external interfa..., Randy Dunlap, (Mon Jan 14, 6:50 pm)

Re: [PATCH] [27/31] CPA: Change comments of external interfa..., Andi Kleen, (Mon Jan 14, 8:49 pm)

[PATCH] [26/31] CPA: Fix reference counting when changing al..., Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [26/31] CPA: Fix reference counting when changin..., Jan Beulich, (Tue Jan 15, 5:05 am)

Re: [PATCH] [26/31] CPA: Fix reference counting when changin..., Andi Kleen, (Tue Jan 15, 6:04 am)

Re: [PATCH] [26/31] CPA: Fix reference counting when changin..., Jan Beulich, (Tue Jan 15, 8:00 am)

[PATCH] [25/31] CPA: Always do full TLB flush when splitting..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [24/31] CPA: Only unmap kernel init pages in text ma..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [23/31] CPA: Remove unnecessary masking of address, Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [22/31] CPA: Only queue actually unused page table p..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [20/31] CPA: Fix inaccurate comments in 64bit change..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [21/31] CPA: Dump pagetable when inconsistency is de..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [19/31] CPA: Limit cache flushing to pages that real..., Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [19/31] CPA: Limit cache flushing to pages that ..., Jan Beulich, (Tue Jan 15, 4:46 am)

[PATCH] [18/31] CPA: Make change_page_attr() more robust aga..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [15/31] CPA: Don't flush the caches when the CPU sup..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [17/31] CPA: Reorder TLB / cache flushes to follow I..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [12/31] CPA: CLFLUSH support in change_page_attr(), Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [12/31] CPA: CLFLUSH support in change_page_attr(), Jan Beulich, (Tue Jan 15, 4:40 am)

Re: [PATCH] [12/31] CPA: CLFLUSH support in change_page_attr(), Andi Kleen, (Tue Jan 15, 5:57 am)

[PATCH] [16/31] CPA: Use wbinvd() macro instead of inline as..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [14/31] CPA: Use page granuality TLB flushing in cha..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [13/31] CPA: Use macros to modify the PG_arch_1 page..., Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [13/31] CPA: Use macros to modify the PG_arch_1 ..., Harvey Harrison, (Tue Jan 15, 5:29 am)

Re: [PATCH] [13/31] CPA: Use macros to modify the PG_arch_1 ..., Andi Kleen, (Tue Jan 15, 6:06 am)

Re: [PATCH] [13/31] CPA: Use macros to modify the PG_arch_1 ..., Harvey Harrison, (Tue Jan 15, 6:15 am)

Re: [PATCH] [13/31] CPA: Use macros to modify the PG_arch_1 ..., Andi Kleen, (Tue Jan 15, 6:25 am)

[PATCH] [11/31] CPA: Change 32bit back to init_mm semaphore ..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [10/31] CPA: Change kernel_map_pages to not use c_p_..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [9/31] CPA: Add simple self test at boot, Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [9/31] CPA: Add simple self test at boot, Harvey Harrison, (Tue Jan 15, 6:37 am)

[PATCH] [8/31] CPA: Return the page table level in lookup_ad..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [7/31] Extract page table dumping code from i386 fau..., Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [7/31] Extract page table dumping code from i386..., Harvey Harrison, (Tue Jan 15, 4:56 am)

Re: [PATCH] [7/31] Extract page table dumping code from i386..., Andi Kleen, (Tue Jan 15, 6:00 am)

Re: [PATCH] [7/31] Extract page table dumping code from i386..., Harvey Harrison, (Tue Jan 15, 6:05 am)

[PATCH] [6/31] CPA: Undo white space changes, Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [5/31] Don't drop NX bit in pte modifier functions f..., Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [4/31] Add pte_pgprot on i386, Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [4/31] Add pte_pgprot on i386, Johannes Weiner, (Tue Jan 15, 9:00 am)

[PATCH] [3/31] Add pte accessors for the global bit, Andi Kleen, (Mon Jan 14, 6:16 pm)

[PATCH] [2/31] CPA: Do a simple self test at boot, Andi Kleen, (Mon Jan 14, 6:16 pm)

Re: [PATCH] [2/31] CPA: Do a simple self test at boot, Harvey Harrison, (Tue Jan 15, 4:47 am)

Re: [PATCH] [2/31] CPA: Do a simple self test at boot, Andi Kleen, (Tue Jan 15, 5:59 am)

Re: [PATCH] [2/31] CPA: Do a simple self test at boot, Harvey Harrison, (Tue Jan 15, 6:07 am)

[PATCH] [1/31] Shrink __PAGE_KERNEL/__PAGE_KERNEL_EXEC on no..., Andi Kleen, (Mon Jan 14, 6:16 pm)

Navigation

Popular discussions


linux-kernel:
david	Re: Dual-Licensing Linux Kernel with GPL V2 and GPL V3
Greg KH	[2.6.22.2 review 05/84] Fix deadlocks in sparc serial console.
Greg KH	[GIT PATCH] driver core patches against 2.6.24
Andrew Morton	-mm merge plans for 2.6.23
git:

linux-netdev:
Jeff Kirsher	[RESEND][NET-NEXT PATCH 01/29] ixgbe: fix bug where using wake queue instead of st...
Gerrit Renker	[PATCH 27/37] dccp: Integration of dynamic feature activation - part 2 (server side)
Jarek Poplawski	[PATCH] pkt_sched: Destroy gen estimators under rtnl_lock().
Patrick McHardy	Re: [GIT]: Networking
netbsd-tech-kern:
Manuel Bouyer	Re: Interactive performance in -current
Christian Limpach	Re: newfs: determining file system parameters
YAMAMOTO Takashi	Re: statvfs(2) replacement for statfs(2) patch
Charles M. Hannum	Re: kern/22869: Slave IDE drive not detected

Colocation donated by:

Who's online

There are currently 2 users and 1063 guests online.

Online users

Syndicate