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Groups > linux.kernel > #1202060
| From | Kamal Mostafa <kamal@canonical.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.13.y-ckt 07/53] x86/nmi/64: Reorder nested NMI checks |
| Date | 2015-08-06 23:00 +0200 |
| Message-ID | <pUAqB-3s1-5@gated-at.bofh.it> (permalink) |
| References | <pUA7f-34H-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
3.13.11-ckt25 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski <luto@kernel.org> commit a27507ca2d796cfa8d907de31ad730359c8a6d06 upstream. Check the repeat_nmi .. end_repeat_nmi special case first. The next patch will rework the RSP check and, as a side effect, the RSP check will no longer detect repeat_nmi .. end_repeat_nmi, so we'll need this ordering of the checks. Note: this is more subtle than it appears. The check for repeat_nmi .. end_repeat_nmi jumps straight out of the NMI code instead of adjusting the "iret" frame to force a repeat. This is necessary, because the code between repeat_nmi and end_repeat_nmi sets "NMI executing" and then writes to the "iret" frame itself. If a nested NMI comes in and modifies the "iret" frame while repeat_nmi is also modifying it, we'll end up with garbage. The old code got this right, as does the new code, but the new code is a bit more explicit. If we were to move the check right after the "NMI executing" check, then we'd get it wrong and have random crashes. This is a prerequisite for the fix for CVE-2015-3291. Signed-off-by: Andy Lutomirski <luto@kernel.org> [bwh: Backported to 4.0: adjust filename, spacing] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kernel/entry_64.S | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 1283ccf..e70afa4 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1869,7 +1869,24 @@ ENTRY(nmi) /* * Determine whether we're a nested NMI. * - * First check "NMI executing". If it's set, then we're nested. + * If we interrupted kernel code between repeat_nmi and + * end_repeat_nmi, then we are a nested NMI. We must not + * modify the "iret" frame because it's being written by + * the outer NMI. That's okay: the outer NMI handler is + * about to about to call do_nmi anyway, so we can just + * resume the outer NMI. + */ + + movq $repeat_nmi, %rdx + cmpq 8(%rsp), %rdx + ja 1f + movq $end_repeat_nmi, %rdx + cmpq 8(%rsp), %rdx + ja nested_nmi_out +1: + + /* + * Now check "NMI executing". If it's set, then we're nested. * This will not detect if we interrupted an outer NMI just * before IRET. */ @@ -1896,21 +1913,6 @@ ENTRY(nmi) nested_nmi: /* - * If we interrupted an NMI that is between repeat_nmi and - * end_repeat_nmi, then we must not modify the "iret" frame - * because it's being written by the outer NMI. That's okay: - * the outer NMI handler is about to call do_nmi anyway, - * so we can just resume the outer NMI. - */ - movq $repeat_nmi, %rdx - cmpq 8(%rsp), %rdx - ja 1f - movq $end_repeat_nmi, %rdx - cmpq 8(%rsp), %rdx - ja nested_nmi_out - -1: - /* * Modify the "iret" frame to point to repeat_nmi, forcing another * iteration of NMI handling. */ -- 1.9.1 -- 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/
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[3.13.y-ckt stable] Linux 3.13.11-ckt25 stable review Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:40 +0200 [PATCH 3.13.y-ckt 37/53] USB: serial: Destroy serial_minors IDR on module exit Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 44/53] genirq: Prevent resend to interrupts marked IRQ_NESTED_THREAD Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 01/53] x86/asm/entry/64: Fold the 'test_in_nmi' macro into its only user Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 47/53] bridge: mdb: zero out the local br_ip variable before use Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 49/53] net: graceful exit from netif_alloc_netdev_queues() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 45/53] ip_tunnel: fix ipv4 pmtu check to honor inner ip header df Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 24/53] iio: adc: at91_adc: allow to use full range of startup time Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 29/53] USB: cp210x: add ID for Aruba Networks controllers Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 28/53] USB: option: add 2020:4000 ID Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 11/53] Btrfs: use kmem_cache_free when freeing entry in inode cache Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 50/53] net: dsa: Fix off-by-one in switch address parsing Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 10/53] sg_start_req(): make sure that there's not too many elements in iovec Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 25/53] ALSA: usb-audio: Add MIDI support for Steinberg MI2/MI4 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 38/53] Btrfs: fix memory leak in the extent_same ioctl Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 13/53] Btrfs: fix fsync data loss after append write Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 19/53] hpfs: kstrdup() out of memory handling Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 34/53] ARM: dts: mx23: fix iio-hwmon support Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 46/53] bridge: mdb: start delete timer for temp static entries Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 41/53] st: null pointer dereference panic caused by use after kref_put by st_open Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 40/53] s390/process: fix sfpc inline assembly Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 33/53] drm: add a check for x/y in drm_mode_setcrtc Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 15/53] ext4: be more strict when migrating to non-extent based file Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 02/53] x86/asm/entry/64: Remove a redundant jump Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 35/53] tracing: Have branch tracer use recursive field of task struct Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 27/53] dm btree remove: fix bug in redistribute3 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 32/53] s390/sclp: clear upper register halves in _sclp_print_early Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 30/53] dm btree: silence lockdep lock inversion in dm_btree_del() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 26/53] iio: tmp006: Check channel info on write Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 36/53] drivers: net: cpsw: fix crash while accessing second slave ethernet interface Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 31/53] usb: musb: host: rely on port_mode to call musb_start() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 22/53] iio: inv-mpu: Specify the expected format/precision for write channels Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 42/53] drm/radeon: add a dpm quirk for Sapphire Radeon R9 270X 2GB GDDR5 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 39/53] ARC: make sure instruction_pointer() returns unsigned value Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 23/53] iio: DAC: ad5624r_spi: fix bit shift of output data value Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 14/53] ext4: fix reservation release on invalidatepage for delalloc fs Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200 [PATCH 3.13.y-ckt 07/53] x86/nmi/64: Reorder nested NMI checks Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 21/53] freeing unlinked file indefinitely delayed Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 08/53] x86/nmi/64: Use DF to avoid userspace RSP confusing nested NMI detection Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 16/53] ext4: correctly migrate a file with a hole at the beginning Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 06/53] x86/nmi/64: Improve nested NMI comments Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 05/53] x86/nmi/64: Switch stacks on userspace NMI entry Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 20/53] 9p: don't leave a half-initialized inode sitting around Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 12/53] Btrfs: fix race between caching kthread and returning inode to inode cache Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 03/53] x86/nmi: Enable nested do_nmi handling for 64-bit kernels Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 18/53] ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stage Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 17/53] ext4: replace open coded nofail allocation in ext4_free_blocks() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200 [PATCH 3.13.y-ckt 09/53] KEYS: ensure we free the assoc array edit if edit is valid Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
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