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Groups > linux.kernel > #1202020 > unrolled thread

[3.13.y-ckt stable] Linux 3.13.11-ckt25 stable review

Started byKamal Mostafa <kamal@canonical.com>
First post2015-08-06 22:40 +0200
Last post2015-08-06 23:00 +0200
Articles 8 on this page of 48 — 1 participant

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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

Page 3 of 3 — ← Prev page 1 2 [3]

#1202064 — [PATCH 3.13.y-ckt 06/53] x86/nmi/64: Improve nested NMI comments

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 06/53] x86/nmi/64: Improve nested NMI comments
Message-ID<pUAqB-3s1-15@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Andy Lutomirski <luto@kernel.org>

commit 0b22930ebad563ae97ff3f8d7b9f12060b4c6e6b upstream.

I found the nested NMI documentation to be difficult to follow.
Improve the comments.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
[bwh: Backported to 4.0: adjust filename, context]
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 | 159 ++++++++++++++++++++++++++-------------------
 arch/x86/kernel/nmi.c      |   4 +-
 2 files changed, 93 insertions(+), 70 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 2991779..1283ccf 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1727,11 +1727,12 @@ ENTRY(nmi)
 	 *  If the variable is not set and the stack is not the NMI
 	 *  stack then:
 	 *    o Set the special variable on the stack
-	 *    o Copy the interrupt frame into a "saved" location on the stack
-	 *    o Copy the interrupt frame into a "copy" location on the stack
+	 *    o Copy the interrupt frame into an "outermost" location on the
+	 *      stack
+	 *    o Copy the interrupt frame into an "iret" location on the stack
 	 *    o Continue processing the NMI
 	 *  If the variable is set or the previous stack is the NMI stack:
-	 *    o Modify the "copy" location to jump to the repeate_nmi
+	 *    o Modify the "iret" location to jump to the repeat_nmi
 	 *    o return back to the first NMI
 	 *
 	 * Now on exit of the first NMI, we first clear the stack variable
@@ -1825,18 +1826,60 @@ ENTRY(nmi)
 
 .Lnmi_from_kernel:
 	/*
-	 * Check the special variable on the stack to see if NMIs are
-	 * executing.
+	 * Here's what our stack frame will look like:
+	 * +---------------------------------------------------------+
+	 * | original SS                                             |
+	 * | original Return RSP                                     |
+	 * | original RFLAGS                                         |
+	 * | original CS                                             |
+	 * | original RIP                                            |
+	 * +---------------------------------------------------------+
+	 * | temp storage for rdx                                    |
+	 * +---------------------------------------------------------+
+	 * | "NMI executing" variable                                |
+	 * +---------------------------------------------------------+
+	 * | iret SS          } Copied from "outermost" frame        |
+	 * | iret Return RSP  } on each loop iteration; overwritten  |
+	 * | iret RFLAGS      } by a nested NMI to force another     |
+	 * | iret CS          } iteration if needed.                 |
+	 * | iret RIP         }                                      |
+	 * +---------------------------------------------------------+
+	 * | outermost SS          } initialized in first_nmi;       |
+	 * | outermost Return RSP  } will not be changed before      |
+	 * | outermost RFLAGS      } NMI processing is done.         |
+	 * | outermost CS          } Copied to "iret" frame on each  |
+	 * | outermost RIP         } iteration.                      |
+	 * +---------------------------------------------------------+
+	 * | pt_regs                                                 |
+	 * +---------------------------------------------------------+
+	 *
+	 * The "original" frame is used by hardware.  Before re-enabling
+	 * NMIs, we need to be done with it, and we need to leave enough
+	 * space for the asm code here.
+	 *
+	 * We return by executing IRET while RSP points to the "iret" frame.
+	 * That will either return for real or it will loop back into NMI
+	 * processing.
+	 *
+	 * The "outermost" frame is copied to the "iret" frame on each
+	 * iteration of the loop, so each iteration starts with the "iret"
+	 * frame pointing to the final return target.
+	 */
+
+	/*
+	 * Determine whether we're a nested NMI.
+	 *
+	 * First check "NMI executing".  If it's set, then we're nested.
+	 * This will not detect if we interrupted an outer NMI just
+	 * before IRET.
 	 */
 	cmpl $1, -8(%rsp)
 	je nested_nmi
 
 	/*
-	 * Now test if the previous stack was an NMI stack.
-	 * We need the double check. We check the NMI stack to satisfy the
-	 * race when the first NMI clears the variable before returning.
-	 * We check the variable because the first NMI could be in a
-	 * breakpoint routine using a breakpoint stack.
+	 * Now test if the previous stack was an NMI stack.  This covers
+	 * the case where we interrupt an outer NMI after it clears
+	 * "NMI executing" but before IRET.
 	 */
 	lea	6*8(%rsp), %rdx
 	/* Compare the NMI stack (rdx) with the stack we came from (4*8(%rsp)) */
@@ -1853,9 +1896,11 @@ ENTRY(nmi)
 
 nested_nmi:
 	/*
-	 * Do nothing if we interrupted the fixup in repeat_nmi.
-	 * It's about to repeat the NMI handler, so we are fine
-	 * with ignoring this one.
+	 * 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
@@ -1865,7 +1910,10 @@ nested_nmi:
 	ja nested_nmi_out
 
 1:
-	/* Set up the interrupted NMIs stack to jump to repeat_nmi */
+	/*
+	 * Modify the "iret" frame to point to repeat_nmi, forcing another
+	 * iteration of NMI handling.
+	 */
 	leaq -1*8(%rsp), %rdx
 	movq %rdx, %rsp
 	CFI_ADJUST_CFA_OFFSET 1*8
@@ -1884,60 +1932,23 @@ nested_nmi_out:
 	popq_cfi %rdx
 	CFI_RESTORE rdx
 
-	/* No need to check faults here */
+	/* We are returning to kernel mode, so this cannot result in a fault. */
 	INTERRUPT_RETURN
 
 	CFI_RESTORE_STATE
 first_nmi:
-	/*
-	 * Because nested NMIs will use the pushed location that we
-	 * stored in rdx, we must keep that space available.
-	 * Here's what our stack frame will look like:
-	 * +-------------------------+
-	 * | original SS             |
-	 * | original Return RSP     |
-	 * | original RFLAGS         |
-	 * | original CS             |
-	 * | original RIP            |
-	 * +-------------------------+
-	 * | temp storage for rdx    |
-	 * +-------------------------+
-	 * | NMI executing variable  |
-	 * +-------------------------+
-	 * | copied SS               |
-	 * | copied Return RSP       |
-	 * | copied RFLAGS           |
-	 * | copied CS               |
-	 * | copied RIP              |
-	 * +-------------------------+
-	 * | Saved SS                |
-	 * | Saved Return RSP        |
-	 * | Saved RFLAGS            |
-	 * | Saved CS                |
-	 * | Saved RIP               |
-	 * +-------------------------+
-	 * | pt_regs                 |
-	 * +-------------------------+
-	 *
-	 * The saved stack frame is used to fix up the copied stack frame
-	 * that a nested NMI may change to make the interrupted NMI iret jump
-	 * to the repeat_nmi. The original stack frame and the temp storage
-	 * is also used by nested NMIs and can not be trusted on exit.
-	 */
-	/* Do not pop rdx, nested NMIs will corrupt that part of the stack */
+	/* Restore rdx. */
 	movq (%rsp), %rdx
 	CFI_RESTORE rdx
 
-	/* Set the NMI executing variable on the stack. */
+	/* Set "NMI executing" on the stack. */
 	pushq_cfi $1
 
-	/*
-	 * Leave room for the "copied" frame
-	 */
+	/* Leave room for the "iret" frame */
 	subq $(5*8), %rsp
 	CFI_ADJUST_CFA_OFFSET 5*8
 
-	/* Copy the stack frame to the Saved frame */
+	/* Copy the "original" frame to the "outermost" frame */
 	.rept 5
 	pushq_cfi 11*8(%rsp)
 	.endr
@@ -1945,6 +1956,7 @@ first_nmi:
 
 	/* Everything up to here is safe from nested NMIs */
 
+repeat_nmi:
 	/*
 	 * If there was a nested NMI, the first NMI's iret will return
 	 * here. But NMIs are still enabled and we can take another
@@ -1953,16 +1965,21 @@ first_nmi:
 	 * it will just return, as we are about to repeat an NMI anyway.
 	 * This makes it safe to copy to the stack frame that a nested
 	 * NMI will update.
-	 */
-repeat_nmi:
-	/*
-	 * Update the stack variable to say we are still in NMI (the update
-	 * is benign for the non-repeat case, where 1 was pushed just above
-	 * to this very stack slot).
+	 *
+	 * RSP is pointing to "outermost RIP".  gsbase is unknown, but, if
+	 * we're repeating an NMI, gsbase has the same value that it had on
+	 * the first iteration.  paranoid_entry will load the kernel
+	 * gsbase if needed before we call do_nmi.
+	 *
+	 * Set "NMI executing" in case we came back here via IRET.
 	 */
 	movq $1, 10*8(%rsp)
 
-	/* Make another copy, this one may be modified by nested NMIs */
+	/*
+	 * Copy the "outermost" frame to the "iret" frame.  NMIs that nest
+	 * here must not modify the "iret" frame while we're writing to
+	 * it or it will end up containing garbage.
+	 */
 	addq $(10*8), %rsp
 	CFI_ADJUST_CFA_OFFSET -10*8
 	.rept 5
@@ -1973,9 +1990,9 @@ repeat_nmi:
 end_repeat_nmi:
 
 	/*
-	 * Everything below this point can be preempted by a nested
-	 * NMI if the first NMI took an exception and reset our iret stack
-	 * so that we repeat another NMI.
+	 * Everything below this point can be preempted by a nested NMI.
+	 * If this happens, then the inner NMI will change the "iret"
+	 * frame to point back to repeat_nmi.
 	 */
 	pushq_cfi $-1		/* ORIG_RAX: no syscall to restart */
 	subq $ORIG_RAX-R15, %rsp
@@ -2000,11 +2017,17 @@ end_repeat_nmi:
 nmi_swapgs:
 	SWAPGS_UNSAFE_STACK
 nmi_restore:
-	/* Pop the extra iret frame at once */
+
 	RESTORE_ALL 6*8
 
-	/* Clear the NMI executing stack variable */
+	/* Clear "NMI executing". */
 	movq $0, 5*8(%rsp)
+
+	/*
+	 * INTERRUPT_RETURN reads the "iret" frame and exits the NMI
+	 * stack in a single instruction.  We are returning to kernel
+	 * mode, so this cannot result in a fault.
+	 */
 	jmp irq_return
 	CFI_ENDPROC
 END(nmi)
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index b82e0fd..85ede73 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -392,8 +392,8 @@ static __kprobes void default_do_nmi(struct pt_regs *regs)
 }
 
 /*
- * NMIs can hit breakpoints which will cause it to lose its NMI context
- * with the CPU when the breakpoint or page fault does an IRET.
+ * NMIs can page fault or hit breakpoints which will cause it to lose
+ * its NMI context with the CPU when the breakpoint or page fault does an IRET.
  *
  * As a result, NMIs can nest if NMIs get unmasked due an IRET during
  * NMI processing.  On x86_64, the asm glue protects us from nested NMIs
-- 
1.9.1

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#1202065 — [PATCH 3.13.y-ckt 05/53] x86/nmi/64: Switch stacks on userspace NMI entry

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 05/53] x86/nmi/64: Switch stacks on userspace NMI entry
Message-ID<pUAqC-3s1-19@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Andy Lutomirski <luto@kernel.org>

commit 9b6e6a8334d56354853f9c255d1395c2ba570e0a upstream.

Returning to userspace is tricky: IRET can fail, and ESPFIX can
rearrange the stack prior to IRET.

The NMI nesting fixup relies on a precise stack layout and atomic
IRET.  Rather than trying to teach the NMI nesting fixup to handle
ESPFIX and failed IRET, punt: run NMIs that came from user mode on
the normal kernel stack.

This will make some nested NMIs visible to C code, but the C code is
okay with that.

As a side effect, this should speed up perf: it eliminates an RDMSR
when NMIs come from user mode.

Fixes CVE-2015-3290.

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
[bwh: Backported to 4.0:
 - Adjust filename, context
 - s/restore_c_regs_and_iret/restore_args/
 - Use kernel_stack + KERNEL_STACK_OFFSET instead of cpu_current_top_of_stack]
[luto: Open-coded return path to avoid dependency on partial pt_regs details]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
CVE-2015-3290, CVE-2015-5157
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 | 79 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 75 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 2cd55a8..2991779 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1740,19 +1740,90 @@ ENTRY(nmi)
 	 * a nested NMI that updated the copy interrupt stack frame, a
 	 * jump will be made to the repeat_nmi code that will handle the second
 	 * NMI.
+	 *
+	 * However, espfix prevents us from directly returning to userspace
+	 * with a single IRET instruction.  Similarly, IRET to user mode
+	 * can fault.  We therefore handle NMIs from user space like
+	 * other IST entries.
 	 */
 
 	/* Use %rdx as out temp variable throughout */
 	pushq_cfi %rdx
 	CFI_REL_OFFSET rdx, 0
 
+	testb	$3, CS-RIP+8(%rsp)
+	jz	.Lnmi_from_kernel
+
 	/*
-	 * If %cs was not the kernel segment, then the NMI triggered in user
-	 * space, which means it is definitely not nested.
+	 * NMI from user mode.  We need to run on the thread stack, but we
+	 * can't go through the normal entry paths: NMIs are masked, and
+	 * we don't want to enable interrupts, because then we'll end
+	 * up in an awkward situation in which IRQs are on but NMIs
+	 * are off.
 	 */
-	cmpl $__KERNEL_CS, 16(%rsp)
-	jne first_nmi
 
+	SWAPGS
+	cld
+	movq	%rsp, %rdx
+	movq	PER_CPU_VAR(kernel_stack), %rsp
+	addq	$KERNEL_STACK_OFFSET, %rsp
+	pushq	5*8(%rdx)	/* pt_regs->ss */
+	pushq	4*8(%rdx)	/* pt_regs->rsp */
+	pushq	3*8(%rdx)	/* pt_regs->flags */
+	pushq	2*8(%rdx)	/* pt_regs->cs */
+	pushq	1*8(%rdx)	/* pt_regs->rip */
+	pushq   $-1		/* pt_regs->orig_ax */
+	pushq   %rdi		/* pt_regs->di */
+	pushq   %rsi		/* pt_regs->si */
+	pushq   (%rdx)		/* pt_regs->dx */
+	pushq   %rcx		/* pt_regs->cx */
+	pushq   %rax		/* pt_regs->ax */
+	pushq   %r8		/* pt_regs->r8 */
+	pushq   %r9		/* pt_regs->r9 */
+	pushq   %r10		/* pt_regs->r10 */
+	pushq   %r11		/* pt_regs->r11 */
+	pushq	%rbx		/* pt_regs->rbx */
+	pushq	%rbp		/* pt_regs->rbp */
+	pushq	%r12		/* pt_regs->r12 */
+	pushq	%r13		/* pt_regs->r13 */
+	pushq	%r14		/* pt_regs->r14 */
+	pushq	%r15		/* pt_regs->r15 */
+
+	/*
+	 * At this point we no longer need to worry about stack damage
+	 * due to nesting -- we're on the normal thread stack and we're
+	 * done with the NMI stack.
+	 */
+
+	movq	%rsp, %rdi
+	movq	$-1, %rsi
+	call	do_nmi
+
+	/*
+	 * Return back to user mode.  We must *not* do the normal exit
+	 * work, because we don't want to enable interrupts.  Fortunately,
+	 * do_nmi doesn't modify pt_regs.
+	 */
+	SWAPGS
+
+	/*
+	 * Open-code the entire return process for compatibility with varying
+	 * register layouts across different kernel versions.
+	 */
+	addq	$6*8, %rsp	/* skip bx, bp, and r12-r15 */
+	popq	%r11		/* pt_regs->r11 */
+	popq	%r10		/* pt_regs->r10 */
+	popq	%r9		/* pt_regs->r9 */
+	popq	%r8		/* pt_regs->r8 */
+	popq	%rax		/* pt_regs->ax */
+	popq	%rcx		/* pt_regs->cx */
+	popq	%rdx		/* pt_regs->dx */
+	popq	%rsi		/* pt_regs->si */
+	popq	%rdi		/* pt_regs->di */
+	addq	$8, %rsp	/* skip orig_ax */
+	INTERRUPT_RETURN
+
+.Lnmi_from_kernel:
 	/*
 	 * Check the special variable on the stack to see if NMIs are
 	 * executing.
-- 
1.9.1

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#1202066 — [PATCH 3.13.y-ckt 20/53] 9p: don't leave a half-initialized inode sitting around

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 20/53] 9p: don't leave a half-initialized inode sitting around
Message-ID<pUAqC-3s1-21@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Al Viro <viro@zeniv.linux.org.uk>

commit 0a73d0a204a4a04a1e110539c5a524ae51f91d6d upstream.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 fs/9p/vfs_inode.c      | 3 +--
 fs/9p/vfs_inode_dotl.c | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 4e65aa9..5a80d7a 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -533,8 +533,7 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	unlock_new_inode(inode);
 	return inode;
 error:
-	unlock_new_inode(inode);
-	iput(inode);
+	iget_failed(inode);
 	return ERR_PTR(retval);
 
 }
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 4c10edec2..5d73779 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -149,8 +149,7 @@ static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 	unlock_new_inode(inode);
 	return inode;
 error:
-	unlock_new_inode(inode);
-	iput(inode);
+	iget_failed(inode);
 	return ERR_PTR(retval);
 
 }
-- 
1.9.1

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#1202068 — [PATCH 3.13.y-ckt 12/53] Btrfs: fix race between caching kthread and returning inode to inode cache

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 12/53] Btrfs: fix race between caching kthread and returning inode to inode cache
Message-ID<pUAqC-3s1-25@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Filipe Manana <fdmanana@suse.com>

commit ae9d8f17118551bedd797406a6768b87c2146234 upstream.

While the inode cache caching kthread is calling btrfs_unpin_free_ino(),
we could have a concurrent call to btrfs_return_ino() that adds a new
entry to the root's free space cache of pinned inodes. This concurrent
call does not acquire the fs_info->commit_root_sem before adding a new
entry if the caching state is BTRFS_CACHE_FINISHED, which is a problem
because the caching kthread calls btrfs_unpin_free_ino() after setting
the caching state to BTRFS_CACHE_FINISHED and therefore races with
the task calling btrfs_return_ino(), which is adding a new entry, while
the former (caching kthread) is navigating the cache's rbtree, removing
and freeing nodes from the cache's rbtree without acquiring the spinlock
that protects the rbtree.

This race resulted in memory corruption due to double free of struct
btrfs_free_space objects because both tasks can end up doing freeing the
same objects. Note that adding a new entry can result in merging it with
other entries in the cache, in which case those entries are freed.
This is particularly important as btrfs_free_space structures are also
used for the block group free space caches.

This memory corruption can be detected by a debugging kernel, which
reports it with the following trace:

[132408.501148] slab error in verify_redzone_free(): cache `btrfs_free_space': double free detected
[132408.505075] CPU: 15 PID: 12248 Comm: btrfs-ino-cache Tainted: G        W       4.1.0-rc5-btrfs-next-10+ #1
[132408.505075] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[132408.505075]  ffff880023e7d320 ffff880163d73cd8 ffffffff8145eec7 ffffffff81095dce
[132408.505075]  ffff880009735d40 ffff880163d73ce8 ffffffff81154e1e ffff880163d73d68
[132408.505075]  ffffffff81155733 ffffffffa054a95a ffff8801b6099f00 ffffffffa0505b5f
[132408.505075] Call Trace:
[132408.505075]  [<ffffffff8145eec7>] dump_stack+0x4f/0x7b
[132408.505075]  [<ffffffff81095dce>] ? console_unlock+0x356/0x3a2
[132408.505075]  [<ffffffff81154e1e>] __slab_error.isra.28+0x25/0x36
[132408.505075]  [<ffffffff81155733>] __cache_free+0xe2/0x4b6
[132408.505075]  [<ffffffffa054a95a>] ? __btrfs_add_free_space+0x2f0/0x343 [btrfs]
[132408.505075]  [<ffffffffa0505b5f>] ? btrfs_unpin_free_ino+0x8e/0x99 [btrfs]
[132408.505075]  [<ffffffff810f3b30>] ? time_hardirqs_off+0x15/0x28
[132408.505075]  [<ffffffff81084d42>] ? trace_hardirqs_off+0xd/0xf
[132408.505075]  [<ffffffff811563a1>] ? kfree+0xb6/0x14e
[132408.505075]  [<ffffffff811563d0>] kfree+0xe5/0x14e
[132408.505075]  [<ffffffffa0505b5f>] btrfs_unpin_free_ino+0x8e/0x99 [btrfs]
[132408.505075]  [<ffffffffa0505e08>] caching_kthread+0x29e/0x2d9 [btrfs]
[132408.505075]  [<ffffffffa0505b6a>] ? btrfs_unpin_free_ino+0x99/0x99 [btrfs]
[132408.505075]  [<ffffffff8106698f>] kthread+0xef/0xf7
[132408.505075]  [<ffffffff810f3b08>] ? time_hardirqs_on+0x15/0x28
[132408.505075]  [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad
[132408.505075]  [<ffffffff814653d2>] ret_from_fork+0x42/0x70
[132408.505075]  [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad
[132408.505075] ffff880023e7d320: redzone 1:0x9f911029d74e35b, redzone 2:0x9f911029d74e35b.
[132409.501654] slab: double free detected in cache 'btrfs_free_space', objp ffff880023e7d320
[132409.503355] ------------[ cut here ]------------
[132409.504241] kernel BUG at mm/slab.c:2571!

Therefore fix this by having btrfs_unpin_free_ino() acquire the lock
that protects the rbtree while doing the searches and removing entries.

Fixes: 1c70d8fb4dfa ("Btrfs: fix inode caching vs tree log")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 fs/btrfs/inode-map.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 9f8c7c7..cb5c24c 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -242,6 +242,7 @@ void btrfs_unpin_free_ino(struct btrfs_root *root)
 {
 	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
 	struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
+	spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
 	struct btrfs_free_space *info;
 	struct rb_node *n;
 	u64 count;
@@ -250,23 +251,29 @@ void btrfs_unpin_free_ino(struct btrfs_root *root)
 		return;
 
 	while (1) {
+		bool add_to_ctl = true;
+
+		spin_lock(rbroot_lock);
 		n = rb_first(rbroot);
-		if (!n)
+		if (!n) {
+			spin_unlock(rbroot_lock);
 			break;
+		}
 
 		info = rb_entry(n, struct btrfs_free_space, offset_index);
 		BUG_ON(info->bitmap); /* Logic error */
 
 		if (info->offset > root->cache_progress)
-			goto free;
+			add_to_ctl = false;
 		else if (info->offset + info->bytes > root->cache_progress)
 			count = root->cache_progress - info->offset + 1;
 		else
 			count = info->bytes;
 
-		__btrfs_add_free_space(ctl, info->offset, count);
-free:
 		rb_erase(&info->offset_index, rbroot);
+		spin_unlock(rbroot_lock);
+		if (add_to_ctl)
+			__btrfs_add_free_space(ctl, info->offset, count);
 		kmem_cache_free(btrfs_free_space_cachep, info);
 	}
 }
-- 
1.9.1

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#1202070 — [PATCH 3.13.y-ckt 03/53] x86/nmi: Enable nested do_nmi handling for 64-bit kernels

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 03/53] x86/nmi: Enable nested do_nmi handling for 64-bit kernels
Message-ID<pUAqC-3s1-29@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Andy Lutomirski <luto@kernel.org>

commit 9d05041679904b12c12421cbcf9cb5f4860a8d7b upstream.

32-bit kernels handle nested NMIs in C.  Enable the exact same
handling on 64-bit kernels as well.  This isn't currently necessary,
but it will become necessary once the asm code starts allowing
limited nesting.

This is a prerequisite for the fix for CVE-2015-3290.

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
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/nmi.c | 123 +++++++++++++++++++++-----------------------------
 1 file changed, 52 insertions(+), 71 deletions(-)

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 6fcb49c..b82e0fd 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -392,15 +392,15 @@ static __kprobes void default_do_nmi(struct pt_regs *regs)
 }
 
 /*
- * NMIs can hit breakpoints which will cause it to lose its
- * NMI context with the CPU when the breakpoint does an iret.
- */
-#ifdef CONFIG_X86_32
-/*
- * For i386, NMIs use the same stack as the kernel, and we can
- * add a workaround to the iret problem in C (preventing nested
- * NMIs if an NMI takes a trap). Simply have 3 states the NMI
- * can be in:
+ * NMIs can hit breakpoints which will cause it to lose its NMI context
+ * with the CPU when the breakpoint or page fault does an IRET.
+ *
+ * As a result, NMIs can nest if NMIs get unmasked due an IRET during
+ * NMI processing.  On x86_64, the asm glue protects us from nested NMIs
+ * if the outer NMI came from kernel mode, but we can still nest if the
+ * outer NMI came from user mode.
+ *
+ * To handle these nested NMIs, we have three states:
  *
  *  1) not running
  *  2) executing
@@ -414,15 +414,14 @@ static __kprobes void default_do_nmi(struct pt_regs *regs)
  * (Note, the latch is binary, thus multiple NMIs triggering,
  *  when one is running, are ignored. Only one NMI is restarted.)
  *
- * If an NMI hits a breakpoint that executes an iret, another
- * NMI can preempt it. We do not want to allow this new NMI
- * to run, but we want to execute it when the first one finishes.
- * We set the state to "latched", and the exit of the first NMI will
- * perform a dec_return, if the result is zero (NOT_RUNNING), then
- * it will simply exit the NMI handler. If not, the dec_return
- * would have set the state to NMI_EXECUTING (what we want it to
- * be when we are running). In this case, we simply jump back
- * to rerun the NMI handler again, and restart the 'latched' NMI.
+ * If an NMI executes an iret, another NMI can preempt it. We do not
+ * want to allow this new NMI to run, but we want to execute it when the
+ * first one finishes.  We set the state to "latched", and the exit of
+ * the first NMI will perform a dec_return, if the result is zero
+ * (NOT_RUNNING), then it will simply exit the NMI handler. If not, the
+ * dec_return would have set the state to NMI_EXECUTING (what we want it
+ * to be when we are running). In this case, we simply jump back to
+ * rerun the NMI handler again, and restart the 'latched' NMI.
  *
  * No trap (breakpoint or page fault) should be hit before nmi_restart,
  * thus there is no race between the first check of state for NOT_RUNNING
@@ -445,49 +444,36 @@ enum nmi_states {
 static DEFINE_PER_CPU(enum nmi_states, nmi_state);
 static DEFINE_PER_CPU(unsigned long, nmi_cr2);
 
-#define nmi_nesting_preprocess(regs)					\
-	do {								\
-		if (this_cpu_read(nmi_state) != NMI_NOT_RUNNING) {	\
-			this_cpu_write(nmi_state, NMI_LATCHED);		\
-			return;						\
-		}							\
-		this_cpu_write(nmi_state, NMI_EXECUTING);		\
-		this_cpu_write(nmi_cr2, read_cr2());			\
-	} while (0);							\
-	nmi_restart:
-
-#define nmi_nesting_postprocess()					\
-	do {								\
-		if (unlikely(this_cpu_read(nmi_cr2) != read_cr2()))	\
-			write_cr2(this_cpu_read(nmi_cr2));		\
-		if (this_cpu_dec_return(nmi_state))			\
-			goto nmi_restart;				\
-	} while (0)
-#else /* x86_64 */
+#ifdef CONFIG_X86_64
 /*
- * In x86_64 things are a bit more difficult. This has the same problem
- * where an NMI hitting a breakpoint that calls iret will remove the
- * NMI context, allowing a nested NMI to enter. What makes this more
- * difficult is that both NMIs and breakpoints have their own stack.
- * When a new NMI or breakpoint is executed, the stack is set to a fixed
- * point. If an NMI is nested, it will have its stack set at that same
- * fixed address that the first NMI had, and will start corrupting the
- * stack. This is handled in entry_64.S, but the same problem exists with
- * the breakpoint stack.
+ * In x86_64, we need to handle breakpoint -> NMI -> breakpoint.  Without
+ * some care, the inner breakpoint will clobber the outer breakpoint's
+ * stack.
  *
- * If a breakpoint is being processed, and the debug stack is being used,
- * if an NMI comes in and also hits a breakpoint, the stack pointer
- * will be set to the same fixed address as the breakpoint that was
- * interrupted, causing that stack to be corrupted. To handle this case,
- * check if the stack that was interrupted is the debug stack, and if
- * so, change the IDT so that new breakpoints will use the current stack
- * and not switch to the fixed address. On return of the NMI, switch back
- * to the original IDT.
+ * If a breakpoint is being processed, and the debug stack is being
+ * used, if an NMI comes in and also hits a breakpoint, the stack
+ * pointer will be set to the same fixed address as the breakpoint that
+ * was interrupted, causing that stack to be corrupted. To handle this
+ * case, check if the stack that was interrupted is the debug stack, and
+ * if so, change the IDT so that new breakpoints will use the current
+ * stack and not switch to the fixed address. On return of the NMI,
+ * switch back to the original IDT.
  */
 static DEFINE_PER_CPU(int, update_debug_stack);
+#endif
 
-static inline void nmi_nesting_preprocess(struct pt_regs *regs)
+dotraplinkage notrace __kprobes void
+do_nmi(struct pt_regs *regs, long error_code)
 {
+	if (this_cpu_read(nmi_state) != NMI_NOT_RUNNING) {
+		this_cpu_write(nmi_state, NMI_LATCHED);
+		return;
+	}
+	this_cpu_write(nmi_state, NMI_EXECUTING);
+	this_cpu_write(nmi_cr2, read_cr2());
+nmi_restart:
+
+#ifdef CONFIG_X86_64
 	/*
 	 * If we interrupted a breakpoint, it is possible that
 	 * the nmi handler will have breakpoints too. We need to
@@ -498,22 +484,8 @@ static inline void nmi_nesting_preprocess(struct pt_regs *regs)
 		debug_stack_set_zero();
 		this_cpu_write(update_debug_stack, 1);
 	}
-}
-
-static inline void nmi_nesting_postprocess(void)
-{
-	if (unlikely(this_cpu_read(update_debug_stack))) {
-		debug_stack_reset();
-		this_cpu_write(update_debug_stack, 0);
-	}
-}
 #endif
 
-dotraplinkage notrace __kprobes void
-do_nmi(struct pt_regs *regs, long error_code)
-{
-	nmi_nesting_preprocess(regs);
-
 	nmi_enter();
 
 	inc_irq_stat(__nmi_count);
@@ -523,8 +495,17 @@ do_nmi(struct pt_regs *regs, long error_code)
 
 	nmi_exit();
 
-	/* On i386, may loop back to preprocess */
-	nmi_nesting_postprocess();
+#ifdef CONFIG_X86_64
+	if (unlikely(this_cpu_read(update_debug_stack))) {
+		debug_stack_reset();
+		this_cpu_write(update_debug_stack, 0);
+	}
+#endif
+
+	if (unlikely(this_cpu_read(nmi_cr2) != read_cr2()))
+		write_cr2(this_cpu_read(nmi_cr2));
+	if (this_cpu_dec_return(nmi_state))
+		goto nmi_restart;
 }
 
 void stop_nmi(void)
-- 
1.9.1

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#1202071 — [PATCH 3.13.y-ckt 18/53] ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stage

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 18/53] ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stage
Message-ID<pUAqC-3s1-23@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

commit 0294112ee3135fbd15eaa70015af8283642dd970 upstream.

This effectively reverts the following three commits:

 7bc10388ccdd ACPI / resources: free memory on error in add_region_before()
 0f1b414d1907 ACPI / PNP: Avoid conflicting resource reservations
 b9a5e5e18fbf ACPI / init: Fix the ordering of acpi_reserve_resources()

(commit b9a5e5e18fbf introduced regressions some of which, but not
all, were addressed by commit 0f1b414d1907 and commit 7bc10388ccdd
was a fixup on top of the latter) and causes ACPI fixed hardware
resources to be reserved at the fs_initcall_sync stage of system
initialization.

The story is as follows.  First, a boot regression was reported due
to an apparent resource reservation ordering change after a commit
that shouldn't lead to such changes.  Investigation led to the
conclusion that the problem happened because acpi_reserve_resources()
was executed at the device_initcall() stage of system initialization
which wasn't strictly ordered with respect to driver initialization
(and with respect to the initialization of the pcieport driver in
particular), so a random change causing the device initcalls to be
run in a different order might break things.

The response to that was to attempt to run acpi_reserve_resources()
as soon as we knew that ACPI would be in use (commit b9a5e5e18fbf).
However, that turned out to be too early, because it caused resource
reservations made by the PNP system driver to fail on at least one
system and that failure was addressed by commit 0f1b414d1907.

That fix still turned out to be insufficient, though, because
calling acpi_reserve_resources() before the fs_initcall stage of
system initialization caused a boot regression to happen on the
eCAFE EC-800-H20G/S netbook.  That meant that we only could call
acpi_reserve_resources() at the fs_initcall initialization stage
or later, but then we might just as well call it after the PNP
initalization in which case commit 0f1b414d1907 wouldn't be
necessary any more.

For this reason, the changes made by commit 0f1b414d1907 are reverted
(along with a memory leak fixup on top of that commit), the changes
made by commit b9a5e5e18fbf that went too far are reverted too and
acpi_reserve_resources() is changed into fs_initcall_sync, which
will cause it to be executed after the PNP subsystem initialization
(which is an fs_initcall) and before device initcalls (including
the pcieport driver initialization) which should avoid the initial
issue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=100581
Link: http://marc.info/?t=143092384600002&r=1&w=2
Link: https://bugzilla.kernel.org/show_bug.cgi?id=99831
Link: http://marc.info/?t=143389402600001&r=1&w=2
Fixes: b9a5e5e18fbf "ACPI / init: Fix the ordering of acpi_reserve_resources()"
Reported-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/acpi/osl.c      |  12 +++-
 drivers/acpi/resource.c | 162 ------------------------------------------------
 drivers/pnp/system.c    |  35 +++--------
 include/linux/acpi.h    |  10 ---
 4 files changed, 18 insertions(+), 201 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 65d93f4..bd2e23e 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -169,10 +169,14 @@ static void __init acpi_request_region (struct acpi_generic_address *gas,
 	if (!addr || !length)
 		return;
 
-	acpi_reserve_region(addr, length, gas->space_id, 0, desc);
+	/* Resources are never freed */
+	if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+		request_region(addr, length, desc);
+	else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		request_mem_region(addr, length, desc);
 }
 
-static void __init acpi_reserve_resources(void)
+static int __init acpi_reserve_resources(void)
 {
 	acpi_request_region(&acpi_gbl_FADT.xpm1a_event_block, acpi_gbl_FADT.pm1_event_length,
 		"ACPI PM1a_EVT_BLK");
@@ -201,7 +205,10 @@ static void __init acpi_reserve_resources(void)
 	if (!(acpi_gbl_FADT.gpe1_block_length & 0x1))
 		acpi_request_region(&acpi_gbl_FADT.xgpe1_block,
 			       acpi_gbl_FADT.gpe1_block_length, "ACPI GPE1_BLK");
+
+	return 0;
 }
+fs_initcall_sync(acpi_reserve_resources);
 
 void acpi_os_printf(const char *fmt, ...)
 {
@@ -1785,7 +1792,6 @@ acpi_status __init acpi_os_initialize(void)
 
 acpi_status __init acpi_os_initialize1(void)
 {
-	acpi_reserve_resources();
 	kacpid_wq = alloc_workqueue("kacpid", 0, 1);
 	kacpi_notify_wq = alloc_workqueue("kacpi_notify", 0, 1);
 	kacpi_hotplug_wq = alloc_workqueue("kacpi_hotplug", 0, 1);
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 9e1ea53..0bdacc5 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -26,7 +26,6 @@
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/ioport.h>
-#include <linux/list.h>
 #include <linux/slab.h>
 
 #ifdef CONFIG_X86
@@ -539,164 +538,3 @@ int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
 	return c.count;
 }
 EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
-
-struct reserved_region {
-	struct list_head node;
-	u64 start;
-	u64 end;
-};
-
-static LIST_HEAD(reserved_io_regions);
-static LIST_HEAD(reserved_mem_regions);
-
-static int request_range(u64 start, u64 end, u8 space_id, unsigned long flags,
-			 char *desc)
-{
-	unsigned int length = end - start + 1;
-	struct resource *res;
-
-	res = space_id == ACPI_ADR_SPACE_SYSTEM_IO ?
-		request_region(start, length, desc) :
-		request_mem_region(start, length, desc);
-	if (!res)
-		return -EIO;
-
-	res->flags &= ~flags;
-	return 0;
-}
-
-static int add_region_before(u64 start, u64 end, u8 space_id,
-			     unsigned long flags, char *desc,
-			     struct list_head *head)
-{
-	struct reserved_region *reg;
-	int error;
-
-	reg = kmalloc(sizeof(*reg), GFP_KERNEL);
-	if (!reg)
-		return -ENOMEM;
-
-	error = request_range(start, end, space_id, flags, desc);
-	if (error) {
-		kfree(reg);
-		return error;
-	}
-
-	reg->start = start;
-	reg->end = end;
-	list_add_tail(&reg->node, head);
-	return 0;
-}
-
-/**
- * acpi_reserve_region - Reserve an I/O or memory region as a system resource.
- * @start: Starting address of the region.
- * @length: Length of the region.
- * @space_id: Identifier of address space to reserve the region from.
- * @flags: Resource flags to clear for the region after requesting it.
- * @desc: Region description (for messages).
- *
- * Reserve an I/O or memory region as a system resource to prevent others from
- * using it.  If the new region overlaps with one of the regions (in the given
- * address space) already reserved by this routine, only the non-overlapping
- * parts of it will be reserved.
- *
- * Returned is either 0 (success) or a negative error code indicating a resource
- * reservation problem.  It is the code of the first encountered error, but the
- * routine doesn't abort until it has attempted to request all of the parts of
- * the new region that don't overlap with other regions reserved previously.
- *
- * The resources requested by this routine are never released.
- */
-int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
-			unsigned long flags, char *desc)
-{
-	struct list_head *regions;
-	struct reserved_region *reg;
-	u64 end = start + length - 1;
-	int ret = 0, error = 0;
-
-	if (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
-		regions = &reserved_io_regions;
-	else if (space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
-		regions = &reserved_mem_regions;
-	else
-		return -EINVAL;
-
-	if (list_empty(regions))
-		return add_region_before(start, end, space_id, flags, desc, regions);
-
-	list_for_each_entry(reg, regions, node)
-		if (reg->start == end + 1) {
-			/* The new region can be prepended to this one. */
-			ret = request_range(start, end, space_id, flags, desc);
-			if (!ret)
-				reg->start = start;
-
-			return ret;
-		} else if (reg->start > end) {
-			/* No overlap.  Add the new region here and get out. */
-			return add_region_before(start, end, space_id, flags,
-						 desc, &reg->node);
-		} else if (reg->end == start - 1) {
-			goto combine;
-		} else if (reg->end >= start) {
-			goto overlap;
-		}
-
-	/* The new region goes after the last existing one. */
-	return add_region_before(start, end, space_id, flags, desc, regions);
-
- overlap:
-	/*
-	 * The new region overlaps an existing one.
-	 *
-	 * The head part of the new region immediately preceding the existing
-	 * overlapping one can be combined with it right away.
-	 */
-	if (reg->start > start) {
-		error = request_range(start, reg->start - 1, space_id, flags, desc);
-		if (error)
-			ret = error;
-		else
-			reg->start = start;
-	}
-
- combine:
-	/*
-	 * The new region is adjacent to an existing one.  If it extends beyond
-	 * that region all the way to the next one, it is possible to combine
-	 * all three of them.
-	 */
-	while (reg->end < end) {
-		struct reserved_region *next = NULL;
-		u64 a = reg->end + 1, b = end;
-
-		if (!list_is_last(&reg->node, regions)) {
-			next = list_next_entry(reg, node);
-			if (next->start <= end)
-				b = next->start - 1;
-		}
-		error = request_range(a, b, space_id, flags, desc);
-		if (!error) {
-			if (next && next->start == b + 1) {
-				reg->end = next->end;
-				list_del(&next->node);
-				kfree(next);
-			} else {
-				reg->end = end;
-				break;
-			}
-		} else if (next) {
-			if (!ret)
-				ret = error;
-
-			reg = next;
-		} else {
-			break;
-		}
-	}
-
-	return ret ? ret : error;
-}
-EXPORT_SYMBOL_GPL(acpi_reserve_region);
diff --git a/drivers/pnp/system.c b/drivers/pnp/system.c
index 515f338..49c1720 100644
--- a/drivers/pnp/system.c
+++ b/drivers/pnp/system.c
@@ -7,7 +7,6 @@
  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
  */
 
-#include <linux/acpi.h>
 #include <linux/pnp.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -23,41 +22,25 @@ static const struct pnp_device_id pnp_dev_table[] = {
 	{"", 0}
 };
 
-#ifdef CONFIG_ACPI
-static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
-{
-	u8 space_id = io ? ACPI_ADR_SPACE_SYSTEM_IO : ACPI_ADR_SPACE_SYSTEM_MEMORY;
-	return !acpi_reserve_region(start, length, space_id, IORESOURCE_BUSY, desc);
-}
-#else
-static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
-{
-	struct resource *res;
-
-	res = io ? request_region(start, length, desc) :
-		request_mem_region(start, length, desc);
-	if (res) {
-		res->flags &= ~IORESOURCE_BUSY;
-		return true;
-	}
-	return false;
-}
-#endif
-
 static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
 {
 	char *regionid;
 	const char *pnpid = dev_name(&dev->dev);
 	resource_size_t start = r->start, end = r->end;
-	bool reserved;
+	struct resource *res;
 
 	regionid = kmalloc(16, GFP_KERNEL);
 	if (!regionid)
 		return;
 
 	snprintf(regionid, 16, "pnp %s", pnpid);
-	reserved = __reserve_range(start, end - start + 1, !!port, regionid);
-	if (!reserved)
+	if (port)
+		res = request_region(start, end - start + 1, regionid);
+	else
+		res = request_mem_region(start, end - start + 1, regionid);
+	if (res)
+		res->flags &= ~IORESOURCE_BUSY;
+	else
 		kfree(regionid);
 
 	/*
@@ -66,7 +49,7 @@ static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
 	 * have double reservations.
 	 */
 	dev_info(&dev->dev, "%pR %s reserved\n", r,
-		 reserved ? "has been" : "could not be");
+		 res ? "has been" : "could not be");
 }
 
 static void reserve_resources_of_dev(struct pnp_dev *dev)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 1652d53..d9099b1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -297,9 +297,6 @@ int acpi_check_region(resource_size_t start, resource_size_t n,
 
 int acpi_resources_are_enforced(void);
 
-int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
-			unsigned long flags, char *desc);
-
 #ifdef CONFIG_HIBERNATION
 void __init acpi_no_s4_hw_signature(void);
 #endif
@@ -459,13 +456,6 @@ static inline int acpi_check_region(resource_size_t start, resource_size_t n,
 	return 0;
 }
 
-static inline int acpi_reserve_region(u64 start, unsigned int length,
-				      u8 space_id, unsigned long flags,
-				      char *desc)
-{
-	return -ENXIO;
-}
-
 struct acpi_table_header;
 static inline int acpi_table_parse(char *id,
 				int (*handler)(struct acpi_table_header *))
-- 
1.9.1

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#1202072 — [PATCH 3.13.y-ckt 17/53] ext4: replace open coded nofail allocation in ext4_free_blocks()

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 17/53] ext4: replace open coded nofail allocation in ext4_free_blocks()
Message-ID<pUAqC-3s1-31@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Michal Hocko <mhocko@suse.cz>

commit 7444a072c387a93ebee7066e8aee776954ab0e41 upstream.

ext4_free_blocks is looping around the allocation request and mimics
__GFP_NOFAIL behavior without any allocation fallback strategy. Let's
remove the open coded loop and replace it with __GFP_NOFAIL. Without the
flag the allocator has no way to find out never-fail requirement and
cannot help in any way.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 fs/ext4/mballoc.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 242226a..a948468 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4791,18 +4791,12 @@ do_more:
 		/*
 		 * blocks being freed are metadata. these blocks shouldn't
 		 * be used until this transaction is committed
+		 *
+		 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
+		 * to fail.
 		 */
-	retry:
-		new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
-		if (!new_entry) {
-			/*
-			 * We use a retry loop because
-			 * ext4_free_blocks() is not allowed to fail.
-			 */
-			cond_resched();
-			congestion_wait(BLK_RW_ASYNC, HZ/50);
-			goto retry;
-		}
+		new_entry = kmem_cache_alloc(ext4_free_data_cachep,
+				GFP_NOFS|__GFP_NOFAIL);
 		new_entry->efd_start_cluster = bit;
 		new_entry->efd_group = block_group;
 		new_entry->efd_count = count_clusters;
-- 
1.9.1

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#1202073 — [PATCH 3.13.y-ckt 09/53] KEYS: ensure we free the assoc array edit if edit is valid

FromKamal Mostafa <kamal@canonical.com>
Date2015-08-06 23:00 +0200
Subject[PATCH 3.13.y-ckt 09/53] KEYS: ensure we free the assoc array edit if edit is valid
Message-ID<pUAqC-3s1-35@gated-at.bofh.it>
In reply to#1202020
3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

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

From: Colin Ian King <colin.king@canonical.com>

commit ca4da5dd1f99fe9c59f1709fb43e818b18ad20e0 upstream.

__key_link_end is not freeing the associated array edit structure
and this leads to a 512 byte memory leak each time an identical
existing key is added with add_key().

The reason the add_key() system call returns okay is that
key_create_or_update() calls __key_link_begin() before checking to see
whether it can update a key directly rather than adding/replacing - which
it turns out it can.  Thus __key_link() is not called through
__key_instantiate_and_link() and __key_link_end() must cancel the edit.

CVE-2015-1333

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 security/keys/keyring.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index d46cbc5..eefe216 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1147,9 +1147,11 @@ void __key_link_end(struct key *keyring,
 	if (index_key->type == &key_type_keyring)
 		up_write(&keyring_serialise_link_sem);
 
-	if (edit && !edit->dead_leaf) {
-		key_payload_reserve(keyring,
-				    keyring->datalen - KEYQUOTA_LINK_BYTES);
+	if (edit) {
+		if (!edit->dead_leaf) {
+			key_payload_reserve(keyring,
+				keyring->datalen - KEYQUOTA_LINK_BYTES);
+		}
 		assoc_array_cancel_edit(edit);
 	}
 	up_write(&keyring->sem);
-- 
1.9.1

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