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From: Jeff Dike <jdike@addtoit.com>
To: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>,
	linux-kernel@vger.kernel.org, patches@x86-64.org
Subject: Re: [patches] [PATCH 2.6.21 review I] [4/25] x86: kernel-mode faults pollute current->thead
Date: Mon, 12 Feb 2007 11:42:47 -0500	[thread overview]
Message-ID: <20070212164247.GA5381@ccure.user-mode-linux.org> (raw)
In-Reply-To: <45D0422A.76E4.0078.0@novell.com>

On Mon, Feb 12, 2007 at 09:32:10AM +0000, Jan Beulich wrote:
> This breaks consumers of notify_die() relying on the proper trap number being
> passed, as the call to notify_die() from die() currently reads
> current->thread.trap_no.

Rats, good point.

> Also, you seem to leave other places where trap_no gets set untouched -
> is this intentional (do_debug - probably correct here, kernel_math_error -
> probably incorrect here)?

I did check the other trap handlers.  kernel_math_error calls die,
which calls do_exit(SIGSEGV).  This doesn't seem to allow the process
the opportunity to trap the SIGSEGV and examine the fault information.

> >I looked at i386, and there is a similar situation.  In this case, there is
> >duplicate code setting task->thread.error_code and trapno.  I deleted one,
> >leaving the copy that runs in the case of a userspace fault.
> 
> Likewise.

Yup.  How does this patch look to you?  We set error_code and trap_no
for userspace faults and kernel faults which call die().  We don't set
them for kernelspace faults which are fixed up.

Index: linux-2.6/arch/i386/kernel/traps.c
===================================================================
--- linux-2.6.orig/arch/i386/kernel/traps.c
+++ linux-2.6/arch/i386/kernel/traps.c
@@ -619,6 +619,8 @@ gp_in_vm86:
 
 gp_in_kernel:
 	if (!fixup_exception(regs)) {
+		current->thread.error_code = error_code;
+		current->thread.trap_no = 13;
 		if (notify_die(DIE_GPF, "general protection fault", regs,
 				error_code, 13, SIGSEGV) == NOTIFY_STOP)
 			return;
Index: linux-2.6/arch/x86_64/kernel/traps.c
===================================================================
--- linux-2.6.orig/arch/x86_64/kernel/traps.c
+++ linux-2.6/arch/x86_64/kernel/traps.c
@@ -605,8 +605,11 @@ static void __kprobes do_trap(int trapnr
 		fixup = search_exception_tables(regs->rip);
 		if (fixup)
 			regs->rip = fixup->fixup;
-		else	
+		else {
+			tsk->thread.error_code = error_code;
+			tsk->thread.trap_no = trapnr;
 			die(str, regs, error_code);
+		}
 		return;
 	}
 }


-- 
Work email - jdike at linux dot intel dot com


  reply	other threads:[~2007-02-12 16:50 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-10 11:50 [PATCH 2.6.21 review I] [1/25] x86_64: Add __copy_from_user_nocache Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [2/25] x86_64: Make the NUMA hash function nodemap allocation Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [3/25] i386: Convert i386 PDA code to use %fs Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [4/25] x86: kernel-mode faults pollute current->thead Andi Kleen
2007-02-12  9:32   ` [patches] " Jan Beulich
2007-02-12 16:42     ` Jeff Dike [this message]
2007-02-12 17:01       ` Jan Beulich
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [5/25] i386: revert i386-fix-the-verify_quirk_intel_irqbalance Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [6/25] x86_64: revert x86_64-mm-add-genapic_force Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [7/25] x86: revert x86_64-mm-fix-the-irqbalance-quirk-for-e7320-e7520-e7525 Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [8/25] x86_64: optimize & fix APIC mode setup Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [9/25] x86_64: always use physical delivery mode on > 8 CPUs Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [10/25] x86_64: remove clustered APIC mode Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [11/25] x86: default to physical mode on hotplug CPU kernels Andi Kleen
2007-02-11 11:13   ` Eric W. Biederman
2007-02-12 22:36     ` Andi Kleen
2007-02-12 23:10       ` Eric W. Biederman
2007-02-12 23:51         ` Siddha, Suresh B
2007-02-12 23:43       ` Siddha, Suresh B
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [12/25] x86_64: x86_64-make-the-numa-hash-function-nodemap-allocation fix fix Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [13/25] i386: Fix a typo in an IRQ handler name Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [14/25] x86: Share what's shareable Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [15/25] i386: Only call unreachable_devices() when type 1 is available Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [16/25] i386: Detect and support the E7520 and the 945G/GZ/P/PL Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [17/25] i386: Reserve resources but only when we're sure about them Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [18/25] x86_64: Fix x86_64 ioremap base_address Andi Kleen
2007-02-10 11:58   ` Arjan van de Ven
2007-02-10 12:07     ` Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [19/25] x86: Reject a broken MCFG tables on Asus etc Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [20/25] x86_64: get rid of ARCH_HAVE_XTIME_LOCK Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [21/25] x86_64: a memcpy that tries to reduce cache pressure Andi Kleen
2007-02-12  9:57   ` [patches] " Jan Beulich
2007-02-12 10:25     ` Andi Kleen
2007-02-13 11:27   ` Eric Dumazet
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [22/25] x86_64: use memcpy_uncached_read() in RDMA interrupt handler to reduce packet loss Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [23/25] x86_64: improved iommu documentation Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [24/25] x86_64: do not always end the stack trace with ULONG_MAX Andi Kleen
2007-02-10 11:50 ` [PATCH 2.6.21 review I] [25/25] i386: arch/i386/kernel/e820.c should #include <asm/setup.h Andi Kleen
2007-02-13  7:52 [patches] [PATCH 2.6.21 review I] [4/25] x86: kernel-mode faults pollute current->thead Jan Beulich
2007-02-13 10:00 ` Andi Kleen
2007-02-14 17:51 ` Jeff Dike
2007-02-15  8:01   ` Jan Beulich
2007-02-15 16:23     ` Jeff Dike

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