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  1. 21 Jul, 2019 17 commits
  3. 10 Jul, 2019 23 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.9.185 · 9c51e110
      Greg Kroah-Hartman authored
      9c51e110
    • Ard Biesheuvel's avatar
      arm64: kaslr: keep modules inside module region when KASAN is enabled · dd862509
      Ard Biesheuvel authored 
      commit 6f496a55 upstream.

When KASLR and KASAN are both enabled, we keep the modules where they
are, and randomize the placement of the kernel so it is within 2 GB
of the module region. The reason for this is that putting modules in
the vmalloc region (like we normally do when KASLR is enabled) is not
possible in this case, given that the entire vmalloc region is already
backed by KASAN zero shadow pages, and so allocating dedicated KASAN
shadow space as required by loaded modules is not possible.

The default module allocation window is set to [_etext - 128MB, _etext]
in kaslr.c, which is appropriate for KASLR kernels booted without a
seed or with 'nokaslr' on the command line. However, as it turns out,
it is not quite correct for the KASAN case, since it still intersects
the vmalloc region at the top, where attempts to allocate shadow pages
will collide with the KASAN zero shadow pages, causing a WARN() and all
kinds of other trouble. So cap the top end to MODULES_END explicitly
when running with KASAN.

Cc: <stable@vger.kernel.org> # 4.9+
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
[will: backport to 4.9.y]
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dd862509
    • Robin Gong's avatar
      dmaengine: imx-sdma: remove BD_INTR for channel0 · 6e8aa99a
      Robin Gong authored 
      commit 3f93a4f2 upstream.

It is possible for an irq triggered by channel0 to be received later
after clks are disabled once firmware loaded during sdma probe. If
that happens then clearing them by writing to SDMA_H_INTR won't work
and the kernel will hang processing infinite interrupts. Actually,
don't need interrupt triggered on channel0 since it's pollling
SDMA_H_STATSTOP to know channel0 done rather than interrupt in
current code, just clear BD_INTR to disable channel0 interrupt to
avoid the above case.
This issue was brought by commit 1d069bfa ("dmaengine: imx-sdma:
ack channel 0 IRQ in the interrupt handler") which didn't take care
the above case.

Fixes: 1d069bfa ("dmaengine: imx-sdma: ack channel 0 IRQ in the interrupt handler")
Cc: stable@vger.kernel.org #5.0+
Signed-off-by: default avatarRobin Gong <yibin.gong@nxp.com>
Reported-by: default avatarSven Van Asbroeck <thesven73@gmail.com>
Tested-by: default avatarSven Van Asbroeck <thesven73@gmail.com>
Reviewed-by: default avatarMichael Olbrich <m.olbrich@pengutronix.de>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6e8aa99a
    • Dmitry Korotin's avatar
      MIPS: Add missing EHB in mtc0 -> mfc0 sequence. · dd8f65a7
      Dmitry Korotin authored 
      commit 0b24cae4 upstream.

Add a missing EHB (Execution Hazard Barrier) in mtc0 -> mfc0 sequence.
Without this execution hazard barrier it's possible for the value read
back from the KScratch register to be the value from before the mtc0.

Reproducible on P5600 & P6600.

The hazard is documented in the MIPS Architecture Reference Manual Vol.
III: MIPS32/microMIPS32 Privileged Resource Architecture (MD00088), rev
6.03 table 8.1 which includes:

   Producer | Consumer | Hazard
  ----------|----------|----------------------------
   mtc0     | mfc0     | any coprocessor 0 register
Signed-off-by: default avatarDmitry Korotin <dkorotin@wavecomp.com>
[paul.burton@mips.com:
  - Commit message tweaks.
  - Add Fixes tags.
  - Mark for stable back to v3.15 where P5600 support was introduced.]
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Fixes: 3d8bfdd0 ("MIPS: Use C0_KScratch (if present) to hold PGD pointer.")
Fixes: 829dcc0a ("MIPS: Add MIPS P5600 probe support")
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dd8f65a7
    • Mike Marciniszyn's avatar
      IB/hfi1: Close PSM sdma_progress sleep window · ea663abb
      Mike Marciniszyn authored 
      commit da9de5f8 upstream.

The call to sdma_progress() is called outside the wait lock.

In this case, there is a race condition where sdma_progress() can return
false and the sdma_engine can idle.  If that happens, there will be no
more sdma interrupts to cause the wakeup and the user_sdma xmit will hang.

Fix by moving the lock to enclose the sdma_progress() call.

Also, delete busycount. The need for this was removed by:
commit bcad2913 ("IB/hfi1: Serve the most starved iowait entry first")

Cc: <stable@vger.kernel.org>
Fixes: 77241056 ("IB/hfi1: add driver files")
Reviewed-by: default avatarGary Leshner <Gary.S.Leshner@intel.com>
Signed-off-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ea663abb
    • Wanpeng Li's avatar
      KVM: LAPIC: Fix pending interrupt in IRR blocked by software disable LAPIC · 997ef649
      Wanpeng Li authored 
      commit bb34e690 upstream.

Thomas reported that:

 | Background:
 |
 |    In preparation of supporting IPI shorthands I changed the CPU offline
 |    code to software disable the local APIC instead of just masking it.
 |    That's done by clearing the APIC_SPIV_APIC_ENABLED bit in the APIC_SPIV
 |    register.
 |
 | Failure:
 |
 |    When the CPU comes back online the startup code triggers occasionally
 |    the warning in apic_pending_intr_clear(). That complains that the IRRs
 |    are not empty.
 |
 |    The offending vector is the local APIC timer vector who's IRR bit is set
 |    and stays set.
 |
 | It took me quite some time to reproduce the issue locally, but now I can
 | see what happens.
 |
 | It requires apicv_enabled=0, i.e. full apic emulation. With apicv_enabled=1
 | (and hardware support) it behaves correctly.
 |
 | Here is the series of events:
 |
 |     Guest CPU
 |
 |     goes down
 |
 |       native_cpu_disable()
 |
 | 			apic_soft_disable();
 |
 |     play_dead()
 |
 |     ....
 |
 |     startup()
 |
 |       if (apic_enabled())
 |         apic_pending_intr_clear()	<- Not taken
 |
 |      enable APIC
 |
 |         apic_pending_intr_clear()	<- Triggers warning because IRR is stale
 |
 | When this happens then the deadline timer or the regular APIC timer -
 | happens with both, has fired shortly before the APIC is disabled, but the
 | interrupt was not serviced because the guest CPU was in an interrupt
 | disabled region at that point.
 |
 | The state of the timer vector ISR/IRR bits:
 |
 |     	     	       	        ISR     IRR
 | before apic_soft_disable()    0	      1
 | after apic_soft_disable()     0	      1
 |
 | On startup		      		 0	      1
 |
 | Now one would assume that the IRR is cleared after the INIT reset, but this
 | happens only on CPU0.
 |
 | Why?
 |
 | Because our CPU0 hotplug is just for testing to make sure nothing breaks
 | and goes through an NMI wakeup vehicle because INIT would send it through
 | the boots-trap code which is not really working if that CPU was not
 | physically unplugged.
 |
 | Now looking at a real world APIC the situation in that case is:
 |
 |     	     	       	      	ISR     IRR
 | before apic_soft_disable()    0	      1
 | after apic_soft_disable()     0	      1
 |
 | On startup		      		 0	      0
 |
 | Why?
 |
 | Once the dying CPU reenables interrupts the pending interrupt gets
 | delivered as a spurious interupt and then the state is clear.
 |
 | While that CPU0 hotplug test case is surely an esoteric issue, the APIC
 | emulation is still wrong, Even if the play_dead() code would not enable
 | interrupts then the pending IRR bit would turn into an ISR .. interrupt
 | when the APIC is reenabled on startup.

From SDM 10.4.7.2 Local APIC State After It Has Been Software Disabled
* Pending interrupts in the IRR and ISR registers are held and require
  masking or handling by the CPU.

In Thomas's testing, hardware cpu will not respect soft disable LAPIC
when IRR has already been set or APICv posted-interrupt is in flight,
so we can skip soft disable APIC checking when clearing IRR and set ISR,
continue to respect soft disable APIC when attempting to set IRR.
Reported-by: default avatarRong Chen <rong.a.chen@intel.com>
Reported-by: default avatarFeng Tang <feng.tang@intel.com>
Reported-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rong Chen <rong.a.chen@intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      997ef649
    • Kees Cook's avatar
      arm64, vdso: Define vdso_{start,end} as array · 830d3a71
      Kees Cook authored 
      Commit dbbb08f5 upstream.

Adjust vdso_{start|end} to be char arrays to avoid compile-time analysis
that flags "too large" memcmp() calls with CONFIG_FORTIFY_SOURCE.

Cc: Jisheng Zhang <jszhang@marvell.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      830d3a71
    • Linus Torvalds's avatar
      tty: rocket: fix incorrect forward declaration of 'rp_init()' · a391af9b
      Linus Torvalds authored 
      [ Upstream commit 423ea325 ]

Make the forward declaration actually match the real function
definition, something that previous versions of gcc had just ignored.

This is another patch to fix new warnings from gcc-9 before I start the
merge window pulls.  I don't want to miss legitimate new warnings just
because my system update brought a new compiler with new warnings.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      a391af9b
    • Nikolay Borisov's avatar
      btrfs: Ensure replaced device doesn't have pending chunk allocation · c51e9aab
      Nikolay Borisov authored 
      commit debd1c06 upstream.

Recent FITRIM work, namely bbbf7243 ("btrfs: combine device update
operations during transaction commit") combined the way certain
operations are recoded in a transaction. As a result an ASSERT was added
in dev_replace_finish to ensure the new code works correctly.
Unfortunately I got reports that it's possible to trigger the assert,
meaning that during a device replace it's possible to have an unfinished
chunk allocation on the source device.

This is supposed to be prevented by the fact that a transaction is
committed before finishing the replace oepration and alter acquiring the
chunk mutex. This is not sufficient since by the time the transaction is
committed and the chunk mutex acquired it's possible to allocate a chunk
depending on the workload being executed on the replaced device. This
bug has been present ever since device replace was introduced but there
was never code which checks for it.

The correct way to fix is to ensure that there is no pending device
modification operation when the chunk mutex is acquire and if there is
repeat transaction commit. Unfortunately it's not possible to just
exclude the source device from btrfs_fs_devices::dev_alloc_list since
this causes ENOSPC to be hit in transaction commit.

Fixing that in another way would need to add special cases to handle the
last writes and forbid new ones. The looped transaction fix is more
obvious, and can be easily backported. The runtime of dev-replace is
long so there's no noticeable delay caused by that.
Reported-by: default avatarDavid Sterba <dsterba@suse.com>
Fixes: 391cd9df ("Btrfs: fix unprotected alloc list insertion during the finishing procedure of replace")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c51e9aab
    • Robert Beckett's avatar
      drm/imx: only send event on crtc disable if kept disabled · e537ba03
      Robert Beckett authored 
      commit 5aeab2bf upstream.

The event will be sent as part of the vblank enable during the modeset
if the crtc is not being kept disabled.

Fixes: 5f2f9115 ("drm/imx: atomic phase 3 step 1: Use atomic configuration")
Signed-off-by: default avatarRobert Beckett <bob.beckett@collabora.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e537ba03
    • Robert Beckett's avatar
      drm/imx: notify drm core before sending event during crtc disable · 06a7d357
      Robert Beckett authored 
      commit 78c68e8f upstream.

Notify drm core before sending pending events during crtc disable.
This fixes the first event after disable having an old stale timestamp
by having drm_crtc_vblank_off update the timestamp to now.

This was seen while debugging weston log message:
Warning: computed repaint delay is insane: -8212 msec

This occurred due to:
1. driver starts up
2. fbcon comes along and restores fbdev, enabling vblank
3. vblank_disable_fn fires via timer disabling vblank, keeping vblank
seq number and time set at current value
(some time later)
4. weston starts and does a modeset
5. atomic commit disables crtc while it does the modeset
6. ipu_crtc_atomic_disable sends vblank with old seq number and time

Fixes: a4744786 ("drm/imx: fix crtc vblank state regression")
Signed-off-by: default avatarRobert Beckett <bob.beckett@collabora.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      06a7d357
    • Herbert Xu's avatar
      lib/mpi: Fix karactx leak in mpi_powm · ea683943
      Herbert Xu authored 
      commit c8ea9fce upstream.

Sometimes mpi_powm will leak karactx because a memory allocation
failure causes a bail-out that skips the freeing of karactx.  This
patch moves the freeing of karactx to the end of the function like
everything else so that it can't be skipped.

Reported-by: syzbot+f7baccc38dcc1e094e77@syzkaller.appspotmail.com
Fixes: cdec9cb5 ("crypto: GnuPG based MPI lib - source files...")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: default avatarEric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ea683943
    • Colin Ian King's avatar
      ALSA: usb-audio: fix sign unintended sign extension on left shifts · 443449d4
      Colin Ian King authored 
      commit 2acf5a3e upstream.

There are a couple of left shifts of unsigned 8 bit values that
first get promoted to signed ints and hence get sign extended
on the shift if the top bit of the 8 bit values are set. Fix
this by casting the 8 bit values to unsigned ints to stop the
unintentional sign extension.

Addresses-Coverity: ("Unintended sign extension")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      443449d4
    • Takashi Iwai's avatar
      ALSA: line6: Fix write on zero-sized buffer · 8b449e9d
      Takashi Iwai authored 
      commit 34501219 upstream.

LINE6 drivers allocate the buffers based on the value returned from
usb_maxpacket() calls.  The manipulated device may return zero for
this, and this results in the kmalloc() with zero size (and it may
succeed) while the other part of the driver code writes the packet
data with the fixed size -- which eventually overwrites.

This patch adds a simple sanity check for the invalid buffer size for
avoiding that problem.

Reported-by: syzbot+219f00fb49874dcaea17@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8b449e9d
    • Takashi Sakamoto's avatar
      ALSA: firewire-lib/fireworks: fix miss detection of received MIDI messages · e25f8374
      Takashi Sakamoto authored 
      commit 7fbd1753 upstream.

In IEC 61883-6, 8 MIDI data streams are multiplexed into single
MIDI conformant data channel. The index of stream is calculated by
modulo 8 of the value of data block counter.

In fireworks, the value of data block counter in CIP header has a quirk
with firmware version v5.0.0, v5.7.3 and v5.8.0. This brings ALSA
IEC 61883-1/6 packet streaming engine to miss detection of MIDI
messages.

This commit fixes the miss detection to modify the value of data block
counter for the modulo calculation.

For maintainers, this bug exists since a commit 18f5ed36 ("ALSA:
fireworks/firewire-lib: add support for recent firmware quirk") in Linux
kernel v4.2. There're many changes since the commit.  This fix can be
backported to Linux kernel v4.4 or later. I tagged a base commit to the
backport for your convenience.

Besides, my work for Linux kernel v5.3 brings heavy code refactoring and
some structure members are renamed in 'sound/firewire/amdtp-stream.h'.
The content of this patch brings conflict when merging -rc tree with
this patch and the latest tree. I request maintainers to solve the
conflict to replace 'tx_first_dbc' with 'ctx_data.tx.first_dbc'.

Fixes: df075fee ("ALSA: firewire-lib: complete AM824 data block processing layer")
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e25f8374
    • Colin Ian King's avatar
      ALSA: seq: fix incorrect order of dest_client/dest_ports arguments · 39950c6c
      Colin Ian King authored 
      commit c3ea60c2 upstream.

There are two occurrances of a call to snd_seq_oss_fill_addr where
the dest_client and dest_port arguments are in the wrong order. Fix
this by swapping them around.

Addresses-Coverity: ("Arguments in wrong order")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      39950c6c
    • Eric Biggers's avatar
      crypto: user - prevent operating on larval algorithms · cd6f2066
      Eric Biggers authored 
      commit 21d4120e upstream.

Michal Suchanek reported [1] that running the pcrypt_aead01 test from
LTP [2] in a loop and holding Ctrl-C causes a NULL dereference of
alg->cra_users.next in crypto_remove_spawns(), via crypto_del_alg().
The test repeatedly uses CRYPTO_MSG_NEWALG and CRYPTO_MSG_DELALG.

The crash occurs when the instance that CRYPTO_MSG_DELALG is trying to
unregister isn't a real registered algorithm, but rather is a "test
larval", which is a special "algorithm" added to the algorithms list
while the real algorithm is still being tested.  Larvals don't have
initialized cra_users, so that causes the crash.  Normally pcrypt_aead01
doesn't trigger this because CRYPTO_MSG_NEWALG waits for the algorithm
to be tested; however, CRYPTO_MSG_NEWALG returns early when interrupted.

Everything else in the "crypto user configuration" API has this same bug
too, i.e. it inappropriately allows operating on larval algorithms
(though it doesn't look like the other cases can cause a crash).

Fix this by making crypto_alg_match() exclude larval algorithms.

[1] https://lkml.kernel.org/r/20190625071624.27039-1-msuchanek@suse.de
[2] https://github.com/linux-test-project/ltp/blob/20190517/testcases/kernel/crypto/pcrypt_aead01.cReported-by: default avatarMichal Suchanek <msuchanek@suse.de>
Fixes: a38f7907 ("crypto: Add userspace configuration API")
Cc: <stable@vger.kernel.org> # v3.2+
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      cd6f2066
    • Jann Horn's avatar
      ptrace: Fix ->ptracer_cred handling for PTRACE_TRACEME · d8b99303
      Jann Horn authored 
      commit 6994eefb upstream.

Fix two issues:

When called for PTRACE_TRACEME, ptrace_link() would obtain an RCU
reference to the parent's objective credentials, then give that pointer
to get_cred().  However, the object lifetime rules for things like
struct cred do not permit unconditionally turning an RCU reference into
a stable reference.

PTRACE_TRACEME records the parent's credentials as if the parent was
acting as the subject, but that's not the case.  If a malicious
unprivileged child uses PTRACE_TRACEME and the parent is privileged, and
at a later point, the parent process becomes attacker-controlled
(because it drops privileges and calls execve()), the attacker ends up
with control over two processes with a privileged ptrace relationship,
which can be abused to ptrace a suid binary and obtain root privileges.

Fix both of these by always recording the credentials of the process
that is requesting the creation of the ptrace relationship:
current_cred() can't change under us, and current is the proper subject
for access control.

This change is theoretically userspace-visible, but I am not aware of
any code that it will actually break.

Fixes: 64b875f7 ("ptrace: Capture the ptracer's creds not PT_PTRACE_CAP")
Signed-off-by: default avatarJann Horn <jannh@google.com>
Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d8b99303
    • Paul Burton's avatar
      MIPS: Workaround GCC __builtin_unreachable reordering bug · e7816df0
      Paul Burton authored 
      [ Upstream commit 906d441f ]

Some versions of GCC for the MIPS architecture suffer from a bug which
can lead to instructions from beyond an unreachable statement being
incorrectly reordered into earlier branch delay slots if the unreachable
statement is the only content of a case in a switch statement. This can
lead to seemingly random behaviour, such as invalid memory accesses from
incorrectly reordered loads or stores, and link failures on microMIPS
builds.

See this potential GCC fix for details:

    https://gcc.gnu.org/ml/gcc-patches/2015-09/msg00360.html

Runtime problems resulting from this bug were initially observed using a
maltasmvp_defconfig v4.4 kernel built using GCC 4.9.2 (from a Codescape
SDK 2015.06-05 toolchain), with the result being an address exception
taken after log messages about the L1 caches (during probe of the L2
cache):

    Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff]
    VPE topology {2,2} total 4
    Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
    Primary data cache 64kB, 4-way, PIPT, no aliases, linesize 32 bytes
    <AdEL exception here>

This is early enough that the kernel exception vectors are not in use,
so any further output depends upon the bootloader. This is reproducible
in QEMU where no further output occurs - ie. the system hangs here.
Given the nature of the bug it may potentially be hit with differing
symptoms. The bug is known to affect GCC versions as recent as 7.3, and
it is unclear whether GCC 8 fixed it or just happens not to encounter
the bug in the testcase found at the link above due to differing
optimizations.

This bug can be worked around by placing a volatile asm statement, which
GCC is prevented from reordering past, prior to the
__builtin_unreachable call.

That was actually done already for other reasons by commit 173a3efd
("bug.h: work around GCC PR82365 in BUG()"), but creates problems for
microMIPS builds due to the lack of a .insn directive. The microMIPS ISA
allows for interlinking with regular MIPS32 code by repurposing bit 0 of
the program counter as an ISA mode bit. To switch modes one changes the
value of this bit in the PC. However typical branch instructions encode
their offsets as multiples of 2-byte instruction halfwords, which means
they cannot change ISA mode - this must be done using either an indirect
branch (a jump-register in MIPS terminology) or a dedicated jalx
instruction. In order to ensure that regular branches don't attempt to
target code in a different ISA which they can't actually switch to, the
linker will check that branch targets are code in the same ISA as the
branch.

Unfortunately our empty asm volatile statements don't qualify as code,
and the link for microMIPS builds fails with errors such as:

    arch/mips/mm/dma-default.s:3265: Error: branch to a symbol in another ISA mode
    arch/mips/mm/dma-default.s:5027: Error: branch to a symbol in another ISA mode

Resolve this by adding a .insn directive within the asm statement which
declares that what comes next is code. This may or may not be true,
since we don't really know what comes next, but as this code is in an
unreachable path anyway that doesn't matter since we won't execute it.

We do this in asm/compiler.h & select CONFIG_HAVE_ARCH_COMPILER_H in
order to have this included by linux/compiler_types.h after
linux/compiler-gcc.h. This will result in asm/compiler.h being included
in all C compilations via the -include linux/compiler_types.h argument
in c_flags, which should be harmless.
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Fixes: 173a3efd ("bug.h: work around GCC PR82365 in BUG()")
Patchwork: https://patchwork.linux-mips.org/patch/20270/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-mips@linux-mips.org
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      e7816df0
    • Lucas De Marchi's avatar
      drm/i915/dmc: protect against reading random memory · 0a112705
      Lucas De Marchi authored 
      commit bc7b488b upstream.

While loading the DMC firmware we were double checking the headers made
sense, but in no place we checked that we were actually reading memory
we were supposed to. This could be wrong in case the firmware file is
truncated or malformed.

Before this patch:
	# ls -l /lib/firmware/i915/icl_dmc_ver1_07.bin
	-rw-r--r-- 1 root root  25716 Feb  1 12:26 icl_dmc_ver1_07.bin
	# truncate -s 25700 /lib/firmware/i915/icl_dmc_ver1_07.bin
	# modprobe i915
	# dmesg| grep -i dmc
	[drm:intel_csr_ucode_init [i915]] Loading i915/icl_dmc_ver1_07.bin
	[drm] Finished loading DMC firmware i915/icl_dmc_ver1_07.bin (v1.7)

i.e. it loads random data. Now it fails like below:
	[drm:intel_csr_ucode_init [i915]] Loading i915/icl_dmc_ver1_07.bin
	[drm:csr_load_work_fn [i915]] *ERROR* Truncated DMC firmware, rejecting.
	i915 0000:00:02.0: Failed to load DMC firmware i915/icl_dmc_ver1_07.bin. Disabling runtime power management.
	i915 0000:00:02.0: DMC firmware homepage: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/i915

Before reading any part of the firmware file, validate the input first.

Fixes: eb805623 ("drm/i915/skl: Add support to load SKL CSR firmware.")
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190605235535.17791-1-lucas.demarchi@intel.com
(cherry picked from commit bc7b488b)
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
[ Lucas: backported to 4.9+ adjusting the context ]
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      0a112705
    • Paolo Bonzini's avatar
      KVM: x86: degrade WARN to pr_warn_ratelimited · d271f225
      Paolo Bonzini authored 
      commit 3f16a5c3 upstream.

This warning can be triggered easily by userspace, so it should certainly not
cause a panic if panic_on_warn is set.

Reported-by: syzbot+c03f30b4f4c46bdf8575@syzkaller.appspotmail.com
Suggested-by: default avatarAlexander Potapenko <glider@google.com>
Acked-by: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d271f225
    • Arnd Bergmann's avatar
      clk: sunxi: fix uninitialized access · 05cd6937
      Arnd Bergmann authored 
      commit 4e903450 upstream.

gcc-8 reports an uninitialized variable access in a code path
that we would see with incorrect DTB input:

drivers/clk/sunxi/clk-sun8i-bus-gates.c: In function 'sun8i_h3_bus_gates_init':
drivers/clk/sunxi/clk-sun8i-bus-gates.c:85:27: error: 'clk_parent' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This works around by skipping invalid input and printing a warning
instead if it ever happens. The problem was apparently part of the
initiali driver submission, but older compilers don't notice it.

Fixes: ab6e23a4 ("clk: sunxi: Add H3 clocks support")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      05cd6937
    • Vineet Gupta's avatar
      ARC: handle gcc generated __builtin_trap for older compiler · bd675574
      Vineet Gupta authored 
      commit af1be2e2 upstream.

ARC gcc prior to GNU 2018.03 release didn't have a target specific
__builtin_trap() implementation, generating default abort() call.

Implement the abort() call - emulating what newer gcc does for the same,
as suggested by Arnd.
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bd675574
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