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Groups > linux.kernel > #1517935
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.4 37/69] parisc: Ensure consistent state when switching to kernel stack at syscall entry |
| Date | 2016-11-09 12:10 +0100 |
| Message-ID | <sByVs-6vX-33@gated-at.bofh.it> (permalink) |
| References | <sByC5-69v-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: John David Anglin <dave.anglin@bell.net> commit 6ed518328d0189e0fdf1bb7c73290d546143ea66 upstream. We have one critical section in the syscall entry path in which we switch from the userspace stack to kernel stack. In the event of an external interrupt, the interrupt code distinguishes between those two states by analyzing the value of sr7. If sr7 is zero, it uses the kernel stack. Therefore it's important, that the value of sr7 is in sync with the currently enabled stack. This patch now disables interrupts while executing the critical section. This prevents the interrupt handler to possibly see an inconsistent state which in the worst case can lead to crashes. Interestingly, in the syscall exit path interrupts were already disabled in the critical section which switches back to the userspace stack. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/parisc/kernel/syscall.S | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -106,8 +106,6 @@ linux_gateway_entry: mtsp %r0,%sr4 /* get kernel space into sr4 */ mtsp %r0,%sr5 /* get kernel space into sr5 */ mtsp %r0,%sr6 /* get kernel space into sr6 */ - mfsp %sr7,%r1 /* save user sr7 */ - mtsp %r1,%sr3 /* and store it in sr3 */ #ifdef CONFIG_64BIT /* for now we can *always* set the W bit on entry to the syscall @@ -133,6 +131,14 @@ linux_gateway_entry: depdi 0, 31, 32, %r21 1: #endif + + /* We use a rsm/ssm pair to prevent sr3 from being clobbered + * by external interrupts. + */ + mfsp %sr7,%r1 /* save user sr7 */ + rsm PSW_SM_I, %r0 /* disable interrupts */ + mtsp %r1,%sr3 /* and store it in sr3 */ + mfctl %cr30,%r1 xor %r1,%r30,%r30 /* ye olde xor trick */ xor %r1,%r30,%r1 @@ -147,6 +153,7 @@ linux_gateway_entry: */ mtsp %r0,%sr7 /* get kernel space into sr7 */ + ssm PSW_SM_I, %r0 /* enable interrupts */ STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ mfctl %cr30,%r1 /* get task ptr in %r1 */ LDREG TI_TASK(%r1),%r1
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[PATCH 4.4 00/69] 4.4.31-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 23/69] USB: serial: ftdi_sio: add support for Infineon TriBoard TC2X7 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 27/69] Fix potential infoleak in older kernels Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 32/69] USB: serial: cp210x: fix tiocmget error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 04/69] h8300: fix syscall restarting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 01/69] i2c: xgene: Avoid dma_buffer overrun Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 19/69] ubifs: Fix regression in ubifs_readdir() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 29/69] hv: do not lose pending heartbeat vmbus packets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 31/69] tty: limit terminal size to 4M chars Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 11/69] ALSA: hda - Raise AZX_DCAPS_RIRB_DELAY handling into top drivers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 06/69] mm/list_lru.c: avoid error-path NULL pointer deref Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 20/69] mei: txe: dont clean an unprocessed interrupt cause. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 22/69] USB: serial: fix potential NULL-dereference at probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 18/69] ubifs: Abort readdir upon error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 26/69] GenWQE: Fix bad page access during abort of resource allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 11:50 +0100 [PATCH 4.4 08/69] KEYS: Fix short sprintf buffer in /proc/keys show function Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:00 +0100 [PATCH 4.4 02/69] i2c: core: fix NULL pointer dereference under race condition Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:00 +0100 [PATCH 4.4 07/69] mm: memcontrol: do not recurse in direct reclaim Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:00 +0100 [PATCH 4.4 67/69] kvm: x86: Check memopp before dereference (CVE-2016-8630) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 60/69] cgroup: avoid false positive gcc-6 warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 37/69] parisc: Ensure consistent state when switching to kernel stack at syscall entry Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 46/69] scsi: scsi_debug: Fix memory leak if LBP enabled and module is unloaded Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 39/69] virtio: console: Unlock vqs while freeing buffers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 47/69] scsi: arcmsr: Send SYNCHRONIZE_CACHE command to firmware Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 65/69] usb: dwc3: Fix size used in dma_free_coherent() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 54/69] perf build: Fix traceevent plugins build race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 38/69] virtio_ring: Make interrupt suppression spec compliant Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 57/69] ARM: 8584/1: floppy: avoid gcc-6 warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 51/69] drm/radeon/si_dpm: workaround for SI kickers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 64/69] pwm: Unexport children before chip removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 36/69] ovl: fsync after copy-up Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 42/69] firewire: net: guard against rx buffer overflows Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:10 +0100 [PATCH 4.4 68/69] ubi: fastmap: Fix add_vol() return value test in ubi_attach_fastmap() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:40 +0100 [PATCH 4.4 44/69] mac80211: discard multicast and 4-addr A-MSDUs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:40 +0100 [PATCH 4.4 43/69] firewire: net: fix fragmented datagram_size off-by-one Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:40 +0100 [PATCH 4.4 45/69] scsi: megaraid_sas: Fix data integrity failure for JBOD (passthrough) devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:40 +0100 [PATCH 4.4 69/69] HID: usbhid: add ATEN CS962 to list of quirky devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:40 +0100 [PATCH 4.4 50/69] drm/radeon/si_dpm: Limit clocks on HD86xx part Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 58/69] mm/cma: silence warnings due to max() usage Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 59/69] drm/exynos: fix error handling in exynos_drm_subdrv_open Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 41/69] Input: i8042 - add XMG C504 to keyboard reset table Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 48/69] mmc: dw_mmc-pltfm: fix the potential NULL pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 63/69] UBI: fastmap: scrub PEB when bitflips are detected in a free PEB EC header Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 55/69] x86/xen: fix upper bound of pmd loop in xen_cleanhighmap() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 56/69] powerpc/ptrace: Fix out of bounds array access warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 40/69] dm mirror: fix read error on recovery after default leg failure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 [PATCH 4.4 61/69] smc91x: avoid self-comparison warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-09 12:50 +0100 Re: [PATCH 4.4 00/69] 4.4.31-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-11-09 19:30 +0100 Re: [PATCH 4.4 00/69] 4.4.31-stable review Guenter Roeck <linux@roeck-us.net> - 2016-11-09 20:40 +0100
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