[kernel] r21723 - in dists/sid/linux/debian: . patches patches/bugfix/mips
Aurelien Jarno
aurel32 at moszumanska.debian.org
Sun Aug 10 12:39:26 UTC 2014
Author: aurel32
Date: Sun Aug 10 12:39:26 2014
New Revision: 21723
Log:
* [mips*] Fix FP emulation for unaligned accesses.
Added:
dists/sid/linux/debian/patches/bugfix/mips/MIPS-Remove-BUG_ON-is_fpu_owner-in-do_ade.patch
Modified:
dists/sid/linux/debian/changelog
dists/sid/linux/debian/patches/series
Modified: dists/sid/linux/debian/changelog
==============================================================================
--- dists/sid/linux/debian/changelog Sat Aug 9 22:52:54 2014 (r21722)
+++ dists/sid/linux/debian/changelog Sun Aug 10 12:39:26 2014 (r21723)
@@ -1,3 +1,10 @@
+linux (3.14.15-3) UNRELEASED; urgency=medium
+
+ [ Aurelien Jarno ]
+ * [mips*] Fix FP emulation for unaligned accesses.
+
+ -- Aurelien Jarno <aurel32 at debian.org> Thu, 24 Jul 2014 21:05:08 +0200
+
linux (3.14.15-2) unstable; urgency=medium
[ Aurelien Jarno ]
Added: dists/sid/linux/debian/patches/bugfix/mips/MIPS-Remove-BUG_ON-is_fpu_owner-in-do_ade.patch
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ dists/sid/linux/debian/patches/bugfix/mips/MIPS-Remove-BUG_ON-is_fpu_owner-in-do_ade.patch Sun Aug 10 12:39:26 2014 (r21723)
@@ -0,0 +1,63 @@
+From: Huacai Chen <chenhc at lemote.com>
+Date: Wed, 16 Jul 2014 09:19:16 +0800
+Subject: MIPS: Remove BUG_ON(!is_fpu_owner()) in do_ade()
+Origin: https://git.kernel.org/linus/2e5767a27337812f6850b3fa362419e2f085e5c3
+
+In do_ade(), is_fpu_owner() isn't preempt-safe. For example, when an
+unaligned ldc1 is executed, do_cpu() is called and then FPU will be
+enabled (and TIF_USEDFPU will be set for the current process). Then,
+do_ade() is called because the access is unaligned. If the current
+process is preempted at this time, TIF_USEDFPU will be cleard. So when
+the process is scheduled again, BUG_ON(!is_fpu_owner()) is triggered.
+
+This small program can trigger this BUG in a preemptible kernel:
+
+int main (int argc, char *argv[])
+{
+ double u64[2];
+
+ while (1) {
+ asm volatile (
+ ".set push \n\t"
+ ".set noreorder \n\t"
+ "ldc1 $f3, 4(%0) \n\t"
+ ".set pop \n\t"
+ ::"r"(u64):
+ );
+ }
+
+ return 0;
+}
+
+V2: Remove the BUG_ON() unconditionally due to Paul's suggestion.
+
+Signed-off-by: Huacai Chen <chenhc at lemote.com>
+Signed-off-by: Jie Chen <chenj at lemote.com>
+Signed-off-by: Rui Wang <wangr at lemote.com>
+Cc: <stable at vger.kernel.org>
+Cc: John Crispin <john at phrozen.org>
+Cc: Steven J. Hill <Steven.Hill at imgtec.com>
+Cc: linux-mips at linux-mips.org
+Cc: Fuxin Zhang <zhangfx at lemote.com>
+Cc: Zhangjin Wu <wuzhangjin at gmail.com>
+Cc: stable at vger.kernel.org
+Signed-off-by: Ralf Baechle <ralf at linux-mips.org>
+---
+ arch/mips/kernel/unaligned.c | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
+index 2b35172..e11906d 100644
+--- a/arch/mips/kernel/unaligned.c
++++ b/arch/mips/kernel/unaligned.c
+@@ -690,7 +690,6 @@ static void emulate_load_store_insn(struct pt_regs *regs,
+ case sdc1_op:
+ die_if_kernel("Unaligned FP access in kernel code", regs);
+ BUG_ON(!used_math());
+- BUG_ON(!is_fpu_owner());
+
+ lose_fpu(1); /* Save FPU state for the emulator. */
+ res = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1,
+--
+1.7.10.4
+
Modified: dists/sid/linux/debian/patches/series
==============================================================================
--- dists/sid/linux/debian/patches/series Sat Aug 9 22:52:54 2014 (r21722)
+++ dists/sid/linux/debian/patches/series Sun Aug 10 12:39:26 2014 (r21723)
@@ -69,6 +69,7 @@
bugfix/mips/MIPS-O32-32-bit-Fix-bug-which-can-cause-incorrect-sy.patch
bugfix/mips/MIPS-tlbex-fix-a-missing-statement-for-HUGETLB.patch
bugfix/mips/MIPS-prevent-user-from-setting-FCSR-cause-bits.patch
+bugfix/mips/MIPS-Remove-BUG_ON-is_fpu_owner-in-do_ade.patch
# Miscellaneous bug fixes
bugfix/all/misc-bmp085-Enable-building-as-a-module.patch
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