Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1233586

[PATCH 4.2 029/134] arm64: flush FP/SIMD state correctly after execve()

Show all headers | View raw

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

commit 674c242c9323d3c293fc4f9a3a3a619fe3063290 upstream.

When a task calls execve(), its FP/SIMD state is flushed so that
none of the original program state is observeable by the incoming
program.

However, since this flushing consists of setting the in-memory copy
of the FP/SIMD state to all zeroes, the CPU field is set to CPU 0 as
well, which indicates to the lazy FP/SIMD preserve/restore code that
the FP/SIMD state does not need to be reread from memory if the task
is scheduled again on CPU 0 without any other tasks having entered
userland (or used the FP/SIMD in kernel mode) on the same CPU in the
mean time. If this happens, the FP/SIMD state of the old program will
still be present in the registers when the new program starts.

So set the CPU field to the invalid value of NR_CPUS when performing
the flush, by calling fpsimd_flush_task_state().

Reported-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Reported-by: Janet Liu <janet.liu@spreadtrum.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm64/kernel/fpsimd.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -158,6 +158,7 @@ void fpsimd_thread_switch(struct task_st
 void fpsimd_flush_thread(void)
 {
 	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
+	fpsimd_flush_task_state(current);
 	set_thread_flag(TIF_FOREIGN_FPSTATE);
 }
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 049/134] powerpc/eeh: Probe after unbalanced kref check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 018/134] MIPS: CPS: use 32b accesses to GCRs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 032/134] arm64: compat: fix vfp save/restore across signal handlers in big-endian Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 047/134] pinctrl: at91: fix null pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 006/134] nfc: st-nci: Remove data from ack_pending_q when receiving a SYNC_ACK Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 015/134] rtlwifi: rtl8821ae: Fix an expression that is always false Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 030/134] of/fdt: make memblock maximum physical address arch configurable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 035/134] arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 050/134] powerpc/eeh: Fix fenced PHB caused by eeh_slot_error_detail() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 007/134] nfc: st-nci: Free data with irrelevant NDLC PCB_SYNC value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 017/134] tg3: Fix temperature reporting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 053/134] powerpc: Uncomment and make enable_kernel_vsx() routine available Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 003/134] nfc: st-nci: Fix non accurate comment for st_nci_i2c_read Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 036/134] KVM: arm64: add workaround for Cortex-A57 erratum #852523 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 004/134] NFC: st21nfca: fix use of uninitialized variables in error path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 037/134] arm64: KVM: Disable virtual timer even if the guest is not using it Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 008/134] nfc: netlink: Add check on NFC_ATTR_VENDOR_DATA Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 048/134] powerpc/pseries: Fix corrupted pdn list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 059/134] powerpc/mm: Recompute hash value after a failed update Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 021/134] mac80211: enable assoc check for mesh interfaces Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 029/134] arm64: flush FP/SIMD state correctly after execve() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 019/134] MIPS: math-emu: Allow m{f,t}hc emulation on MIPS R6 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 024/134] cxl: Fix unbalanced pci_dev_get in cxl_probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 002/134] nfc: st-nci: Fix typo when changing from st21nfcb to st-nci Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 022/134] cxl: Allow release of contexts which have been OPENED but not STARTED Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 027/134] arm64: kconfig: Move LIST_POISON to a safe value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 020/134] MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 025/134] ext4: dont manipulate recovery flag when freezing no-journal fs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 028/134] arm64: entry: always restore x0 from the stack on syscall return Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 010/134] nfc: nci: hci: Add check on skb nci_hci_send_cmd parameter Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 026/134] Revert "ext4: remove block_device_ejected" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 023/134] cxl: Remove racy attempt to force EEH invocation in reset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-27 20:20 +0200
    Re: [PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 20:40 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-28 08:00 +0200
    Re: [PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-28 16:30 +0200
      Re: [PATCH 4.2 000/134] 4.2.2-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-28 17:10 +0200
      Re: [PATCH 4.2 000/134] 4.2.2-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-28 17:10 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-09-28 19:40 +0200

csiph-web