linux/arch/mips
Huacai Chen 2e5767a273 MIPS: Remove BUG_ON(!is_fpu_owner()) in do_ade()
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@lemote.com>
Signed-off-by: Jie Chen <chenj@lemote.com>
Signed-off-by: Rui Wang <wangr@lemote.com>
Cc: <stable@vger.kernel.org>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-07-30 21:30:22 +02:00
..
alchemy MIPS: Replace obsolete strict_strto call with kstrto 2014-06-04 22:50:40 +02:00
ar7 MIPS: Restore init.h usage to arch/mips/ar7/time.c 2014-03-26 23:09:23 +01:00
ath79 usb: host: remove selects of USB_ARCH_HAS_?HCI 2014-02-18 12:36:38 -08:00
bcm47xx Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-06-12 14:27:40 -07:00
bcm63xx MIPS: Use current_cpu_type() instead of c->cputype 2014-03-31 18:17:12 +02:00
boot mips: delete non-required instances of include <linux/init.h> 2014-01-24 22:39:56 +01:00
cavium-octeon Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
cobalt
configs Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
dec Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
emma
fw MIPS: DEC/SNI: O32 wrapper stack switching fixes 2014-05-13 00:29:35 +02:00
include MIPS: uasm: Add SLT uasm instruction 2014-06-26 10:48:19 +01:00
jazz
jz4740 ASoC: qi_lb60: Use GPIO descriptor API 2014-04-23 12:18:36 +01:00
kernel MIPS: Remove BUG_ON(!is_fpu_owner()) in do_ade() 2014-07-30 21:30:22 +02:00
kvm MIPS: KVM: Fix memory leak on VCPU 2014-06-25 14:17:03 +02:00
lantiq Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
lasat MIPS: Lasat: Replace del_timer by del_timer_sync 2014-03-31 18:17:12 +02:00
lib MIPS: __delay ABI-dependent subtraction simplification 2014-05-30 21:01:08 +02:00
loongson Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
loongson1 MIPS: Disable MIPS16/microMIPS crap for platforms not supporting these ASEs. 2014-05-23 15:12:37 +02:00
math-emu MIPS: math-emu: Fix instruction decoding. 2014-07-30 19:13:35 +02:00
mm MIPS: tlbex: Fix a missing statement for HUGETLB 2014-07-30 14:34:25 +02:00
mti-malta Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
mti-sead3 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
net MIPS: bpf: Fix stack space allocation for BPF memwords on MIPS64 2014-06-26 10:48:23 +01:00
netlogic Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
oprofile MIPS: Add support for the M5150 processor 2014-03-26 23:09:22 +01:00
paravirt mips: Update the email address of Geert Uytterhoeven 2014-06-02 16:34:41 +02:00
pci Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-06-09 18:10:34 -07:00
pmcs-msp71xx MIPS: MT: Remove SMTC support 2014-05-24 00:07:01 +02:00
pnx833x MIPS: PNX833x: Remove checks for CONFIG_I2C_PNX0105 2014-05-23 15:12:39 +02:00
power MIPS: Hibernate: Flush TLB entries in swsusp_arch_resume() 2014-03-31 10:16:53 +02:00
ralink DeviceTree for 3.16: 2014-06-04 10:02:38 -07:00
rb532 MIPS: RB532: Fix reregistering of serial console 2014-07-30 13:27:51 +02:00
sgi-ip22 MIPS: IP22: Add missing put_device call 2014-07-30 13:27:51 +02:00
sgi-ip27 MIPS: SMP: Remove plat_smp_ops cpus_done method. 2014-05-27 11:06:42 +02:00
sgi-ip32
sibyte MIPS: SMP: Remove plat_smp_ops cpus_done method. 2014-05-27 11:06:42 +02:00
sni
txx9 MIPS: TXx9: 7segled: add missing put_device call 2014-07-30 13:27:51 +02:00
vr41xx
Kbuild MIPS: net: Add BPF JIT 2014-05-30 16:10:20 +02:00
Kbuild.platforms MIPS: Enable build for new system 'paravirt' 2014-06-02 12:34:20 +02:00
Kconfig MIPS: Lasat: Fix build error if CRC32 is not enabled. 2014-06-26 14:43:01 +01:00
Kconfig.debug MIPS: MT: Remove SMTC support 2014-05-24 00:07:01 +02:00
Makefile Merge branch '3.15-fixes' into mips-for-linux-next 2014-06-04 22:53:02 +02:00