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From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
	Nadav Amit <nadav.amit@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	Brian Gerst <brgerst@gmail.com>,
	"kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v4 10/16] x86/die: Don't try to recover from an OOPS on a non-default stack
Date: Thu, 23 Jun 2016 21:23:05 -0700	[thread overview]
Message-ID: <66fc0e6c5a47a0bb8e96c340908067c72a027acc.1466741835.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1466741835.git.luto@kernel.org>
In-Reply-To: <cover.1466741835.git.luto@kernel.org>

It's not going to work, because the scheduler will explode if we try
to schedule when running on an IST stack or similar.

This will matter when we let kernel stack overflows (which are #DF)
call die().

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/kernel/dumpstack.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index d6209f3a69cb..70d5aae8b8f7 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -245,6 +245,9 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 		return;
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
+	if (((current_stack_pointer() ^ (current_top_of_stack() - 1))
+	     & ~(THREAD_SIZE - 1)) != 0)
+		panic("Fatal exception on special stack");
 	if (panic_on_oops)
 		panic("Fatal exception");
 	do_exit(signr);
-- 
2.5.5

  parent reply	other threads:[~2016-06-24  4:25 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-24  4:22 [PATCH v4 00/16] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-24  4:22 ` [PATCH v4 01/16] bluetooth: Switch SMP to crypto_cipher_encrypt_one() Andy Lutomirski
2016-06-24  6:10   ` Herbert Xu
2016-06-24  7:19   ` Johan Hedberg
2016-06-24  4:22 ` [PATCH v4 02/16] rxrpc: Avoid using stack memory in SG lists in rxkad Andy Lutomirski
2016-06-24  4:22 ` [PATCH v4 03/16] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-24  4:22 ` [PATCH v4 04/16] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-24  4:23 ` [PATCH v4 05/16] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski
2016-06-24  4:23 ` [PATCH v4 06/16] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-24 15:21   ` Josh Poimboeuf
2016-06-24  4:23 ` [PATCH v4 07/16] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski
2016-06-24 15:22   ` Josh Poimboeuf
2016-06-24  4:23 ` [PATCH v4 08/16] dma-api: Teach the "DMA-from-stack" check about vmapped stacks Andy Lutomirski
2016-06-24  4:23 ` [PATCH v4 09/16] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-24  4:23 ` Andy Lutomirski [this message]
2016-06-24  4:23 ` [PATCH v4 11/16] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-24 15:30   ` Josh Poimboeuf
2016-06-24 15:35     ` Brian Gerst
2016-06-24 15:48       ` Josh Poimboeuf
2016-06-24  4:23 ` [PATCH v4 12/16] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-24 15:31   ` Josh Poimboeuf
2016-06-24  4:23 ` [PATCH v4 13/16] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-24 15:35   ` Josh Poimboeuf
2016-06-26 16:59     ` Andy Lutomirski
2016-06-24  4:23 ` [PATCH v4 14/16] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-24 15:36   ` Josh Poimboeuf
2016-06-24  4:23 ` [PATCH v4 15/16] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-24  4:23 ` [PATCH v4 16/16] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski

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