[kvm-devel] [PATCH 03 of 12] get_task_mm should not succeed if mmput() is running and has reduced
# HG changeset patch # User Andrea Arcangeli [EMAIL PROTECTED] # Date 1208872186 -7200 # Node ID a6672bdeead0d41b2ebd6846f731d43a611645b7 # Parent 3c804dca25b15017b22008647783d6f5f3801fa9 get_task_mm should not succeed if mmput() is running and has reduced the mm_users count to zero. This can occur if a processor follows a tasks pointer to an mm struct because that pointer is only cleared after the mmput(). If get_task_mm() succeeds after mmput() reduced the mm_users to zero then we have the lovely situation that one portion of the kernel is doing all the teardown work for an mm while another portion is happily using it. Signed-off-by: Christoph Lameter [EMAIL PROTECTED] diff --git a/kernel/fork.c b/kernel/fork.c --- a/kernel/fork.c +++ b/kernel/fork.c @@ -442,7 +442,8 @@ if (task-flags PF_BORROWED_MM) mm = NULL; else - atomic_inc(mm-mm_users); + if (!atomic_inc_not_zero(mm-mm_users)) + mm = NULL; } task_unlock(task); return mm; - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
Re: [kvm-devel] [PATCH 03 of 12] get_task_mm should not succeed if mmput() is running and has reduced
Missing signoff by you. - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
Re: [kvm-devel] [PATCH 03 of 12] get_task_mm should not succeed if mmput() is running and has reduced
On Tue, Apr 22, 2008 at 01:23:16PM -0700, Christoph Lameter wrote: Missing signoff by you. I thought I had to signoff if I conributed with anything that could resemble copyright? Given I only merged that patch, I can add an Acked-by if you like, but merging this in my patchset was already an implicit ack ;-). - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
Re: [kvm-devel] [PATCH 03 of 12] get_task_mm should not succeed if mmput() is running and has reduced
On Wed, 23 Apr 2008, Andrea Arcangeli wrote: On Tue, Apr 22, 2008 at 01:23:16PM -0700, Christoph Lameter wrote: Missing signoff by you. I thought I had to signoff if I conributed with anything that could resemble copyright? Given I only merged that patch, I can add an Acked-by if you like, but merging this in my patchset was already an implicit ack ;-). No you have to include a signoff if the patch goes through your custody chain. This one did. Also add a From: Christoph Lameter [EMAIL PROTECTED] somewhere if you want to signify that the patch came from me. - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
