From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Fri, 07 Mar 2014 12:25:37 +0000 Subject: Re: [patch] x86/efi: use GFP_ATOMIC under spin_lock Message-Id: <20140307122103.GM4774@mwanda> List-Id: References: <20140307112055.GE2351@elgon.mountain> <20140307121022.GA32575@gmail.com> In-Reply-To: <20140307121022.GA32575-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: Matt Fleming , Nathan Zimmer , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Fri, Mar 07, 2014 at 01:10:22PM +0100, Ingo Molnar wrote: > > * Dan Carpenter wrote: > > > In phys_efi_get_time() we call efi_call_phys_prelog() with a spin_lock > > so this allocation should be atomic. > > > > Fixes: b8f2c21db390 ('efi, x86: Pass a proper identity mapping in efi_call_phys_prelog') > > Signed-off-by: Dan Carpenter > > > > diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c > > index 0c2a234fef1e..f5adcadb381b 100644 > > --- a/arch/x86/platform/efi/efi_64.c > > +++ b/arch/x86/platform/efi/efi_64.c > > @@ -90,7 +90,7 @@ void __init efi_call_phys_prelog(void) > > local_irq_save(efi_flags); > > > > n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE); > > - save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL); > > + save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_ATOMIC); > > > > for (pgd = 0; pgd < n_pgds; pgd++) { > > save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE); > > The allocation there, if it happens within a spinlocked path, is > probably a layering violation - and GFP_ATOMIC is at best a > workaround. > You're on your own for fixing the complicated stuff like layering violations. I just do static checker stuff and sed fixes. ;) regards, dan carpenter