It's been widely reported that this patch breaks existing userspace
applications when backported to the stable kernel releases. As no fix
seems to be forthcoming, just revert it to let systems work again.
Reported-by: "J. Paul Reed" <preed@sigkill.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For CONFIG_KALLSYMS, we keep two symbol tables and two string tables.
There's one full copy, marked SHF_ALLOC and laid out at the end of the
module's init section. There's also a cut-down version that only
contains core symbols and strings, and lives in the module's core
section.
After module init (and before we free the module memory), we switch
the mod->symtab, mod->num_symtab and mod->strtab to point to the core
versions. We do this under the module_mutex.
However, kallsyms doesn't take the module_mutex: it uses
preempt_disable() and rcu tricks to walk through the modules, because
it's used in the oops path. It's also used in /proc/kallsyms.
There's nothing atomic about the change of these variables, so we can
get the old (larger!) num_symtab and the new symtab pointer; in fact
this is what I saw when trying to reproduce.
By grouping these variables together, we can use a
carefully-dereferenced pointer to ensure we always get one or the
other (the free of the module init section is already done in an RCU
callback, so that's safe). We allocate the init one at the end of the
module init section, and keep the core one inside the struct module
itself (it could also have been allocated at the end of the module
core, but that's probably overkill).
[ Rebased for 4.4-stable and older, because the following changes aren't
in the older trees:
- e0224418516b4d8a6c2160574bac18447c354ef0: adds arg to is_core_symbol
- 7523e4dc5057e157212b4741abd6256e03404cf1: module_init/module_core/init_size/core_size
become init_layout.base/core_layout.base/init_layout.size/core_layout.size.
'This is because the pstore filesystem can be backed by UEFI variables,
and (for example) a crash might dump the last kilobytes of the dmesg
into a number of pstore entries, each entry backed by a separate UEFI
variable in the above GUID namespace, and with a variable name
according to the above pattern.
Please see "drivers/firmware/efi/efi-pstore.c".
While this patch series will not prevent the user from deleting those
UEFI variables via the pstore filesystem (i.e., deleting a pstore fs
entry will continue to delete the backing UEFI variable), I think it
would be nice to preserve the possibility for the sysadmin to delete
Linux-created UEFI variables that carry portions of the crash log,
*without* having to mount the pstore filesystem.'
There's also no chance of causing machines to become bricked by
deleting these variables, which is the whole purpose of excluding
things from the whitelist.
Use the LINUX_EFI_CRASH_GUID guid and a wildcard '*' for the match so
that we don't have to update the string in the future if new variable
name formats are created for crash dump variables.
Reported-by: Laszlo Ersek <lersek@redhat.com> Acked-by: Peter Jones <pjones@redhat.com> Tested-by: Peter Jones <pjones@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: "Lee, Chun-Yi" <jlee@suse.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
"rm -rf" is bricking some peoples' laptops because of variables being
used to store non-reinitializable firmware driver data that's required
to POST the hardware.
These are 100% bugs, and they need to be fixed, but in the mean time it
shouldn't be easy to *accidentally* brick machines.
We have to have delete working, and picking which variables do and don't
work for deletion is quite intractable, so instead make everything
immutable by default (except for a whitelist), and make tools that
aren't quite so broad-spectrum unset the immutable flag.
Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All the variables in this list so far are defined to be in the global
namespace in the UEFI spec, so this just further ensures we're
validating the variables we think we are.
Including the guid for entries will become more important in future
patches when we decide whether or not to allow deletion of variables
based on presence in this list.
Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Actually translate from ucs2 to utf8 before doing the test, and then
test against our other utf8 data, instead of fudging it.
Signed-off-by: Peter Jones <pjones@redhat.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Translate EFI's UCS-2 variable names to UTF-8 instead of just assuming
all variable names fit in ASCII.
Signed-off-by: Peter Jones <pjones@redhat.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This adds ucs2_utf8size(), which tells us how big our ucs2 string is in
bytes, and ucs2_as_utf8, which translates from ucs2 to utf8..
Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As reported at https://bugs.launchpad.net/qemu/+bug/1494350,
it is possible to have vcpu->arch.st.last_steal initialized
from a thread other than vcpu thread, say the iothread, via
KVM_SET_MSRS.
Which can cause an overflow later (when subtracting from vcpu threads
sched_info.run_delay).
To avoid that, move steal time accumulation to vcpu entry time,
before copying steal time data to guest.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since binutils 2.26 BFD is doing suffix merging on STRTAB sections. But
dedotify modifies the symbol names in place, which can also modify
unrelated symbols with a name that matches a suffix of a dotted name. To
remove the leading dot of a symbol name we can just increment the pointer
into the STRTAB section instead.
Backport to all stables to avoid breakage when people update their
binutils - mpe.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The value 5000 was put here with the addition of the timeout field to
ieee80211_start_tx_ba_session. It was originally added in mac80211 to
save resources for drivers like iwlwifi, which only supports a limited
number of concurrent aggregation sessions.
Since iwlwifi does not use minstrel_ht and other drivers don't need
this, 0 is a better default - especially since there have been
recent reports of aggregation setup related issues reproduced with
ath9k. This should improve stability without causing any adverse
effects.
Acked-by: Avery Pennarun <apenwarr@gmail.com> Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Beniamino reported that he was getting an RTM_NEWLINK message for a
given interface, after the RTM_DELLINK for it. It turns out that the
message is a wireless extensions message, which was sent because the
interface had been connected and disconnection while it was deleted
caused a wext message.
For its netlink messages, wext uses RTM_NEWLINK, but the message is
without all the regular rtnetlink attributes, so "ip monitor link"
prints just rudimentary information:
5: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default
link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff
Deleted 5: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default
link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff
5: wlan1: <BROADCAST,MULTICAST,UP>
link/ether
(from my hwsim reproduction)
This can cause userspace to get confused since it doesn't expect an
RTM_NEWLINK message after RTM_DELLINK.
The reason for this is that wext schedules a worker to send out the
messages, and the scheduling delay can cause the messages to get out
to userspace in different order.
To fix this, have wext register a netdevice notifier and flush out
any pending messages when netdevice state changes. This fixes any
ordering whenever the original message wasn't sent by a notifier
itself.
"MBC Mode", "VSS Mode", "VSS HPF Mode" and "Enhanced EQ Mode" ctls in
wm8958 codec driver are enum, while the current driver accesses
wrongly via value.integer.value[]. They have to be via
value.enumerated.item[] instead.
Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DRC Mode like "AIF1DRC1 Mode" and EQ Mode like "AIF1.1 EQ Mode" in
wm8994 codec driver are enum ctls, while the current driver accesses
wrongly via value.integer.value[]. They have to be via
value.enumerated.item[] instead.
Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit f37755490fe9b ("tracepoints: Do not trace when cpu is offline") added
a check to make sure that tracepoints only get called when the cpu is
online, as it uses rcu_read_lock_sched() for protection.
Commit 3a630178fd5f3 ("tracing: generate RCU warnings even when tracepoints
are disabled") added lockdep checks (including rcu checks) for events that
are not enabled to catch possible RCU issues that would only be triggered if
a trace event was enabled. Commit f37755490fe9b only stopped the warnings
when the trace event was enabled but did not prevent warnings if the trace
event was called when disabled.
To fix this, the cpu online check is moved to where the condition is added
to the trace event. This will place the cpu online check in all places that
it may be used now and in the future.
Fixes: f37755490fe9b ("tracepoints: Do not trace when cpu is offline") Fixes: 3a630178fd5f3 ("tracing: generate RCU warnings even when tracepoints are disabled") Reported-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux guests on Haswell (and also SandyBridge and Broadwell, at least)
would crash if you decided to run a host command that uses PEBS, like
perf record -e 'cpu/mem-stores/pp' -a
This happens because KVM is using VMX MSR switching to disable PEBS, but
SDM [2015-12] 18.4.4.4 Re-configuring PEBS Facilities explains why it
isn't safe:
When software needs to reconfigure PEBS facilities, it should allow a
quiescent period between stopping the prior event counting and setting
up a new PEBS event. The quiescent period is to allow any latent
residual PEBS records to complete its capture at their previously
specified buffer address (provided by IA32_DS_AREA).
There might not be a quiescent period after the MSR switch, so a CPU
ends up using host's MSR_IA32_DS_AREA to access an area in guest's
memory. (Or MSR switching is just buggy on some models.)
The guest can learn something about the host this way:
If the guest doesn't map address pointed by MSR_IA32_DS_AREA, it results
in #PF where we leak host's MSR_IA32_DS_AREA through CR2.
After that, a malicious guest can map and configure memory where
MSR_IA32_DS_AREA is pointing and can therefore get an output from
host's tracing.
This is not a critical leak as the host must initiate with PEBS tracing
and I have not been able to get a record from more than one instruction
before vmentry in vmx_vcpu_run() (that place has most registers already
overwritten with guest's).
We could disable PEBS just few instructions before vmentry, but
disabling it earlier shouldn't affect host tracing too much.
We also don't need to switch MSR_IA32_PEBS_ENABLE on VMENTRY, but that
optimization isn't worth its code, IMO.
(If you are implementing PEBS for guests, be sure to handle the case
where both host and guest enable PEBS, because this patch doesn't.)
Fixes: 26a4f3c08de4 ("perf/x86: disable PEBS on a guest entry.") Reported-by: Jiří Olša <jolsa@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Parrot NMEA GPS Flight Recorder is a USB composite device
consisting of hub, flash storage, and cp210x usb to serial chip.
It is an accessory to the mass-produced Parrot AR Drone 2.
The device emits standard NMEA messages which make the it compatible
with NMEA compatible software. It was tested using gpsd version 3.11-3
as an NMEA interpreter and using the official Parrot Flight Recorder.
The timer user status compat ioctl returned the bogus struct used for
64bit architectures instead of the 32bit one. This patch addresses
it to return the proper struct.
HDSPM driver contains a code issuing zero-division potentially in
system sample rate ctl code. This patch fixes it by not processing
a zero or invalid rate value as a divisor, as well as excluding the
invalid value to be passed via the given ctl element.
The OSS sequencer client tries to drain the pending events at
releasing. Unfortunately, as spotted by syzkaller fuzzer, this may
lead to an unkillable process state when the event has been queued at
the far future. Since the process being released can't be signaled
any longer, it remains and waits for the echo-back event in that far
future.
Back to history, the draining feature was implemented at the time we
misinterpreted POSIX definition for blocking file operation.
Actually, such a behavior is superfluous at release, and we should
just release the device as is instead of keeping it up forever.
This patch just removes the draining call that may block the release
for too long time unexpectedly.
X32 ABI takes the 64bit timespec, thus the timer user status ioctl becomes
incompatible with IA32. This results in NOTTY error when the ioctl is
issued.
Meanwhile, this struct in X32 is essentially identical with the one in
X86-64, so we can just bypassing to the existing code for this
specific compat ioctl.
Like the previous fixes for ctl and PCM, we need a fix for
incompatible X32 ABI regarding the rawmidi: namely, struct
snd_rawmidi_status has the timespec, and the size and the alignment on
X32 differ from IA32.
The X32 ABI takes the same alignment like x86-64, and this may result
in the incompatible struct size from ia32. Unfortunately, we hit this
in some control ABI: struct snd_ctl_elem_value differs between them
due to the position of 64bit variable array. This ends up with the
unknown ioctl (ENOTTY) error.
The fix is to add the compat entries for the new aligned struct.
When a directory is deleted, we don't take too much care about killing off
all the dirents that belong to it — on the basis that on remount, the scan
will conclude that the directory is dead anyway.
This doesn't work though, when the deleted directory contained a child
directory which was moved *out*. In the early stages of the fs build
we can then end up with an apparent hard link, with the child directory
appearing both in its true location, and as a child of the original
directory which are this stage of the mount process we don't *yet* know
is defunct.
To resolve this, take out the early special-casing of the "directories
shall not have hard links" rule in jffs2_build_inode_pass1(), and let the
normal nlink processing happen for directories as well as other inodes.
Then later in the build process we can set ic->pino_nlink to the parent
inode#, as is required for directories during normal operaton, instead
of the nlink. And complain only *then* about hard links which are still
in evidence even after killing off all the unreachable paths.
Reported-by: Liu Song <liu.song11@zte.com.cn> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With this fix, all code paths should now be obtaining the page lock before
f->sem.
Reported-by: Szabó Tamás <sztomi89@gmail.com> Tested-by: Thomas Betker <thomas.betker@rohde-schwarz.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 5ffd3412ae55
("jffs2: Fix lock acquisition order bug in jffs2_write_begin").
The commit modified jffs2_write_begin() to remove a deadlock with
jffs2_garbage_collect_live(), but this introduced new deadlocks found
by multiple users. page_lock() actually has to be called before
mutex_lock(&c->alloc_sem) or mutex_lock(&f->sem) because
jffs2_write_end() and jffs2_readpage() are called with the page locked,
and they acquire c->alloc_sem and f->sem, resp.
In other words, the lock order in jffs2_write_begin() was correct, and
it is the jffs2_garbage_collect_live() path that has to be changed.
Revert the commit to get rid of the new deadlocks, and to clear the way
for a better fix of the original deadlock.
Reported-by: Deng Chao <deng.chao1@zte.com.cn> Reported-by: Ming Liu <liu.ming50@gmail.com> Reported-by: wangzaiwei <wangzaiwei@top-vision.cn> Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pause/unpause graph tracing around do_suspend_lowlevel as it has
inconsistent call/return info after it jumps to the wakeup vector.
The graph trace buffer will otherwise become misaligned and
may eventually crash and hang on suspend.
To reproduce the issue and test the fix:
Run a function_graph trace over suspend/resume and set the graph
function to suspend_devices_and_enter. This consistently hangs the
system without this fix.
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The id buffer in ata_device is a DMA target, but it isn't explicitly
cacheline aligned. Due to this, adjacent fields can be overwritten with
stale data from memory on non coherent architectures. As a result, the
kernel is sometimes unable to communicate with an ATA device.
Fix this by ensuring that the id buffer is cacheline aligned.
This issue is similar to that fixed by Commit 84bda12af31f
("libata: align ap->sector_buf").
As reported by Soohoon Lee, the HDIO_GET_32BIT ioctl does not
work correctly in compat mode with libata.
I have investigated the issue further and found multiple problems
that all appeared with the same commit that originally introduced
HDIO_GET_32BIT handling in libata back in linux-2.6.8 and presumably
also linux-2.4, as the code uses "copy_to_user(arg, &val, 1)" to copy
a 'long' variable containing either 0 or 1 to user space.
The problems with this are:
* On big-endian machines, this will always write a zero because it
stores the wrong byte into user space.
* In compat mode, the upper three bytes of the variable are updated
by the compat_hdio_ioctl() function, but they now contain
uninitialized stack data.
* The hdparm tool calling this ioctl uses a 'static long' variable
to store the result. This means at least the upper bytes are
initialized to zero, but calling another ioctl like HDIO_GET_MULTCOUNT
would fill them with data that remains stale when the low byte
is overwritten. Fortunately libata doesn't implement any of the
affected ioctl commands, so this would only happen when we query
both an IDE and an ATA device in the same command such as
"hdparm -N -c /dev/hda /dev/sda"
* The libata code for unknown reasons started using ATA_IOC_GET_IO32
and ATA_IOC_SET_IO32 as aliases for HDIO_GET_32BIT and HDIO_SET_32BIT,
while the ioctl commands that were added later use the normal
HDIO_* names. This is harmless but rather confusing.
This addresses all four issues by changing the code to use put_user()
on an 'unsigned long' variable in HDIO_GET_32BIT, like the IDE subsystem
does, and by clarifying the names of the ioctl commands.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reported-by: Soohoon Lee <Soohoon.Lee@f5.com> Tested-by: Soohoon Lee <Soohoon.Lee@f5.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During DRAM initialization on certain ASpeed devices, an incorrect
bit (bit 10) was checked in the "SDRAM Bus Width Status" register
to determine DRAM width.
Query bit 6 instead in accordance with the Aspeed AST2050 datasheet v1.05.
For interim responses we only need to parse a header and update
a number credits. Now it is done for all SMB2+ command except
SMB2_READ which is wrong. Fix this by adding such processing.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org> Tested-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I get the splat below when modprobing/rmmoding EDAC drivers. It happens
because bus->name is invalid after bus_unregister() has run. The Code: section
below corresponds to:
Dmitry reported that he was able to reproduce the WARN_ON_ONCE that
fires in locks_free_lock_context when the flc_posix list isn't empty.
The problem turns out to be that we're basically rebuilding the
file_lock from scratch in fcntl_setlk when we discover that the setlk
has raced with a close. If the l_whence field is SEEK_CUR or SEEK_END,
then we may end up with fl_start and fl_end values that differ from
when the lock was initially set, if the file position or length of the
file has changed in the interim.
Fix this by just reusing the same lock request structure, and simply
override fl_type value with F_UNLCK as appropriate. That ensures that
we really are unlocking the lock that was initially set.
While we're there, make sure that we do pop a WARN_ON_ONCE if the
removal ever fails. Also return -EBADF in this event, since that's
what we would have returned if the close had happened earlier.
Cc: Alexander Viro <viro@zeniv.linux.org.uk> Fixes: c293621bbf67 (stale POSIX lock handling) Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When we call pci_scan_root_bus we would pass in 'sd' (sysdata)
pointer which was an 'pcifront_sd' structure. However in the
pci_device_add it expects that the 'sd' is 'struct sysdata' and
sets the dev->node to what is in sd->node (offset 4):
That is an hole - filled with garbage as we used kmalloc instead of
kzalloc (the second problem).
This patch fixes the issue by:
1) Use kzalloc to initialize to a well known state.
2) Put 'struct pci_sysdata' at the start of 'pcifront_sd'. That
way access to the 'node' will access the right offset.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
... into returning a positive to path_openat(), which would interpret that
as "symlink had been encountered" and proceed to corrupt memory, etc.
It can only happen due to a bug in some ->open() instance or in some LSM
hook, etc., so we report any such event *and* make sure it doesn't trick
us into further unpleasantness.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In __request_region, if a conflict with a BUSY and MUXED resource is
detected, then the caller goes to sleep and waits for the resource to be
released. A pointer on the conflicting resource is kept. At wake-up
this pointer is used as a parent to retry to request the region.
A first problem is that this pointer might well be invalid (if for
example the conflicting resource have already been freed). Another
problem is that the next call to __request_region() fails to detect a
remaining conflict. The previously conflicting resource is passed as a
parameter and __request_region() will look for a conflict among the
children of this resource and not at the resource itself. It is likely
to succeed anyway, even if there is still a conflict.
Instead, the parent of the conflicting resource should be passed to
__request_region().
As a fix, this patch doesn't update the parent resource pointer in the
case we have to wait for a muxed region right after.
Reported-and-tested-by: Vincent Pelletier <plr.vincent@gmail.com> Signed-off-by: Simon Guinot <simon.guinot@sequanux.org> Tested-by: Vincent Donnefort <vdonnefort@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The qword_get() function NUL-terminates its output buffer. If the input
string is in hex format \xXXXX... and the same length as the output
buffer, there is an off-by-one:
This patch ensures the NUL terminator doesn't fall outside the output
buffer.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ftrace:function event is only displayed for parsing the function tracer
data. It is not used to enable function tracing, and does not include an
"enable" file in its event directory.
Originally, this event was kept separate from other events because it did
not have a ->reg parameter. But perf added a "reg" parameter for its use
which caused issues, because it made the event available to functions where
it was not compatible for.
Commit 9b63776fa3ca9 "tracing: Do not enable function event with enable"
added a TRACE_EVENT_FL_IGNORE_ENABLE flag that prevented the function event
from being enabled by normal trace events. But this commit missed keeping
the function event from being displayed by the "available_events" directory,
which is used to show what events can be enabled by set_event.
One documented way to enable all events is to:
cat available_events > set_event
But because the function event is displayed in the available_events, this
now causes an INVALID error:
cat: write error: Invalid argument
Reported-by: Chunyu Hu <chuhu@redhat.com> Fixes: 9b63776fa3ca9 "tracing: Do not enable function event with enable" Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In async_pf we try to allocate with NOWAIT to get an element quickly
or fail. This code also handle failures gracefully. Lets silence
potential page allocation failures under load.
A Root Port's AER structure (rpc) contains a queue of events. aer_irq()
enqueues AER status information and schedules aer_isr() to dequeue and
process it. When we remove a device, aer_remove() waits for the queue to
be empty, then frees the rpc struct.
But aer_isr() references the rpc struct after dequeueing and possibly
emptying the queue, which can cause a use-after-free error as in the
following scenario with two threads, aer_isr() on the left and a
concurrent aer_remove() on the right:
Thread A Thread B
-------- --------
aer_irq():
rpc->prod_idx++
aer_remove():
wait_event(rpc->prod_idx == rpc->cons_idx)
# now blocked until queue becomes empty
aer_isr(): # ...
rpc->cons_idx++ # unblocked because queue is now empty
... kfree(rpc)
mutex_unlock(&rpc->rpc_mutex)
To prevent this problem, use flush_work() to wait until the last scheduled
instance of aer_isr() has completed before freeing the rpc struct in
aer_remove().
I reproduced this use-after-free by flashing a device FPGA and
re-enumerating the bus to find the new device. With SLUB debug, this
crashes with 0x6b bytes (POISON_FREE, the use-after-free magic number) in
GPR25:
The bulk of ATA host state machine is implemented by
ata_sff_hsm_move(). The function is called from either the interrupt
handler or, if polling, a work item. Unlike from the interrupt path,
the polling path calls the function without holding the host lock and
ata_sff_hsm_move() selectively grabs the lock.
This is completely broken. If an IRQ triggers while polling is in
progress, the two can easily race and end up accessing the hardware
and updating state machine state at the same time. This can put the
state machine in an illegal state and lead to a crash like the
following.
Fix it by ensuring that the polling path is holding the host lock
before entering ata_sff_hsm_move() so that all hardware accesses and
state updates are performed under the host lock.
Workqueue used to implicity guarantee that work items queued without
explicit CPU specified are put on the local CPU. Recent changes in
timer broke the guarantee and led to vmstat breakage which was fixed
by 176bed1de5bf ("vmstat: explicitly schedule per-cpu work on the CPU
we need it to run on").
vmstat is the most likely to expose the issue and it's quite possible
that there are other similar problems which are a lot more difficult
to trigger. As a preventive measure, 874bbfe600a6 ("workqueue: make
sure delayed work run in local cpu") was applied to restore the local
CPU guarnatee. Unfortunately, the change exposed a bug in timer code
which got fixed by 22b886dd1018 ("timers: Use proper base migration in
add_timer_on()"). Due to code restructuring, the commit couldn't be
backported beyond certain point and stable kernels which only had 874bbfe600a6 started crashing.
The local CPU guarantee was accidental more than anything else and we
want to get rid of it anyway. As, with the vmstat case fixed, 874bbfe600a6 is causing more problems than it's fixing, it has been
decided to take the chance and officially break the guarantee by
reverting the commit. A debug feature will be added to force foreign
CPU assignment to expose cases relying on the guarantee and fixes for
the individual cases will be backported to stable as necessary.
Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 874bbfe600a6 ("workqueue: make sure delayed work run in local cpu") Link: http://lkml.kernel.org/g/20160120211926.GJ10810@quack.suse.cz Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: Daniel Bilik <daniel.bilik@neosystem.cz> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shli@fb.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Bilik <daniel.bilik@neosystem.cz> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The code within wait_event_interruptible() is called with
!TASK_RUNNING, so mustn't call any functions that can sleep,
like mutex_lock().
Since we re-check the list_empty() in a loop after the wait,
it's safe to simply use list_empty() without locking.
This bug has existed forever, but was only discovered now
because all userspace implementations, including the default
'rfkill' tool, use poll() or select() to get a readable fd
before attempting to read.
The contract between try_read() and try_write() is that when called
each processes as much data as possible. When instructed by osd_client
to skip a message, try_read() is violating this contract by returning
after receiving and discarding a single message instead of checking for
more. try_write() then gets a chance to write out more requests,
generating more replies/skips for try_read() to handle, forcing the
messenger into a starvation loop.
Reported-by: Varada Kari <Varada.Kari@sandisk.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Tested-by: Varada Kari <Varada.Kari@sandisk.com> Reviewed-by: Alex Elder <elder@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to use post-decrement to get the pci_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if pci_map_page
failed already at i==0.
Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Clark <robdclark@gmail.com> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>. Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The value returned by sys_personality has type "long int".
It is saved to a variable of type "int", which is not a problem
yet because the type of task_struct->pesonality is "unsigned int".
The problem is the sign extension from "int" to "long int"
that happens on return from sys_sparc64_personality.
For example, a userspace call personality((unsigned) -EINVAL) will
result to any subsequent personality call, including absolutely
harmless read-only personality(0xffffffff) call, failing with
errno set to EINVAL.
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4956e10903fd ("ARM: 6244/1: mmci: add variant data and default
MCICLOCK support") added variant data for ARM, U300 and Ux500 variants.
The Nomadik NHK8815/8820 variant was erroneously labeled as a U300
variant, and when the proper Nomadik variant was later introduced in
commit 34fd421349ff ("ARM: 7378/1: mmci: add support for the Nomadik MMCI
variant") this was not fixes. Let's say this fixes the latter commit as
there was no proper Nomadik support until then.
Fixes: 34fd421349ff ("ARM: 7378/1: mmci: add support for the Nomadik...") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The posix_clock_poll function is supposed to return a bit mask of
POLLxxx values. However, in case the hardware has disappeared (due to
hot plugging for example) this code returns -ENODEV in a futile
attempt to throw an error at the file descriptor level. The kernel's
file_operations interface does not accept such error codes from the
poll method. Instead, this function aught to return POLLERR.
The value -ENODEV does, in fact, contain the POLLERR bit (and almost
all the other POLLxxx bits as well), but only by chance. This patch
fixes code to return a proper bit mask.
Credit goes to Markus Elfring for pointing out the suspicious
signed/unsigned mismatch.
Reported-by: Markus Elfring <elfring@users.sourceforge.net>
igned-off-by: Richard Cochran <richardcochran@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Julia Lawall <julia.lawall@lip6.fr> Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When there is an error copying a chunk dm-snapshot can incorrectly hold
associated bios indefinitely, resulting in hung IO.
The function copy_callback sets pe->error if there was error copying the
chunk, and then calls complete_exception. complete_exception calls
pending_complete on error, otherwise it calls commit_exception with
commit_callback (and commit_callback calls complete_exception).
The persistent exception store (dm-snap-persistent.c) assumes that calls
to prepare_exception and commit_exception are paired.
persistent_prepare_exception increases ps->pending_count and
persistent_commit_exception decreases it.
If there is a copy error, persistent_prepare_exception is called but
persistent_commit_exception is not. This results in the variable
ps->pending_count never returning to zero and that causes some pending
exceptions (and their associated bios) to be held forever.
Fix this by unconditionally calling commit_exception regardless of
whether the copy was successful. A new "valid" parameter is added to
commit_exception -- when the copy fails this parameter is set to zero so
that the chunk that failed to copy (and all following chunks) is not
recorded in the snapshot store. Also, remove commit_callback now that
it is merely a wrapper around pending_complete.
The tda1004x was updating the properties cache before locking.
If the device is not locked, the data at the registers are just
random values with no real meaning.
This caused the driver to fail with libdvbv5, as such library
calls GET_PROPERTY from time to time, in order to return the
DVB stats.
Tested with a saa7134 card 78:
ASUSTeK P7131 Dual, vendor PCI ID: 1043:4862
v4l2-compliance sends a zeroed struct v4l2_streamparm in
v4l2-test-formats.cpp::testParmType(), and this results in a division by
0 in some gspca subdrivers:
Let's also get rid of the "cosmic ray protection" while we're at it.
Fixes: e9193059b1b3 "hostfs: fix races in dentry_name() and inode_name()" Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The channel checks the specified length and the provided amount of
data for CCWs and provides an incorrect length error if the size does
not match. Under z/VM with simulation activated the length may get
changed. Having the suppress length indication bit set is stated as
good CCW coding practice and avoids errors under z/VM.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The normalization pass in the sorting routine of the relative exception
table serves two purposes:
- it ensures that the address fields of the exception table entries are
fully ordered, so that no ambiguities arise between entries with
identical instruction offsets (i.e., when two instructions that are
exactly 8 bytes apart each have an exception table entry associated with
them)
- it ensures that the offsets of both the instruction and the fixup fields
of each entry are relative to their final location after sorting.
Commit eb608fb366de ("s390/exceptions: switch to relative exception table
entries") ported the relative exception table format from x86, but modified
the sorting routine to only normalize the instruction offset field and not
the fixup offset field. The result is that the fixup offset of each entry
will be relative to the original location of the entry before sorting,
likely leading to crashes when those entries are dereferenced.
We weren't accounting for the insertion of an inline extent item for the
symlink inode nor that we need to update the parent inode item (through
the call to btrfs_add_nondir()). So fix this by including two more
transaction units.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a symlink is successfully created it always has an inline extent
containing the source path. However if an error happens when creating
the symlink, we can leave in the subvolume's tree a symlink inode without
any such inline extent item - this happens if after btrfs_symlink() calls
btrfs_end_transaction() and before it calls the inode eviction handler
(through the final iput() call), the transaction gets committed and a
crash happens before the eviction handler gets called, or if a snapshot
of the subvolume is made before the eviction handler gets called. Sadly
we can't just avoid this by making btrfs_symlink() call
btrfs_end_transaction() after it calls the eviction handler, because the
later can commit the current transaction before it removes any items from
the subvolume tree (if it encounters ENOSPC errors while reserving space
for removing all the items).
So make send fail more gracefully, with an -EIO error, and print a
message to dmesg/syslog informing that there's an empty symlink inode,
so that the user can delete the empty symlink or do something else
about it.
Reported-by: Stephen R. van den Berg <srb@cuci.nl> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We hit this panic on a few of our boxes this week where we have an
ordered_extent with an NULL inode. We do an igrab() of the inode in writepages,
but weren't doing it in writepage which can be called directly from the VM on
dirty pages. If the inode has been unlinked then we could have I_FREEING set
which means igrab() would return NULL and we get this panic. Fix this by trying
to igrab in btrfs_writepage, and if it returns NULL then just redirty the page
and return AOP_WRITEPAGE_ACTIVATE; so the VM knows it wasn't successful. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Looks like oversight, call brelse() when checksum fails. Further down the
code, in the non error path, we do call brelse() and so we don't see
brelse() in the goto error paths.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
recordmcount edits the file in-place, which can cause problems when
using ccache in hardlink mode. Arrange for recordmcount to break a
hardlinked object.
KASAN found that our additional element processing scripts drop off
the end of the VPD page into unallocated space. The reason is that
not every element has additional information but our traversal
routines think they do, leading to them expecting far more additional
information than is present. Fix this by adding a gate to the
traversal routine so that it only processes elements that are expected
to have additional information (list is in SES-2 section 6.1.13.1:
Additional Element Status diagnostic page overview)
Reported-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Tested-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Simple enclosure implementations (mostly USB) are allowed to return only
page 8 to every diagnostic query. That really confuses our
implementation because we assume the return is the page we asked for and
end up doing incorrect offsets based on bogus information leading to
accesses outside of allocated ranges. Fix that by checking the page
code of the return and giving an error if it isn't the one we asked for.
This should fix reported bugs with USB storage by simply refusing to
attach to enclosures that behave like this. It's also good defensive
practise now that we're starting to see more USB enclosures.
Reported-by: Andrea Gelmini <andrea.gelmini@gelma.net> Reviewed-by: Ewan D. Milne <emilne@redhat.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some users of rfkill, like NFC and cfg80211, use a dynamic name when
allocating rfkill, in those cases dev_name(). Therefore, the pointer
passed to rfkill_alloc() might not be valid forever, I specifically
found the case that the rfkill name was quite obviously an invalid
pointer (or at least garbage) when the wiphy had been renamed.
Fix this by making a copy of the rfkill name in rfkill_alloc().
Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If dm_btree_del()'s call to push_frame() fails, e.g. due to
btree_node_validator finding invalid metadata, the dm_btree_del() error
path must unlock all frames (which have active dm-bufio buffers) that
were pushed onto the del_stack.
Otherwise, dm_bufio_client_destroy() will BUG_ON() because dm-bufio
buffers have leaked, e.g.:
device-mapper: bufio: leaked buffer 3, hold count 1, list 0
Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When I connect an Intel SSD to SATA SIL controller (PCI ID 1095:3114), any
TRIM command results in I/O errors being reported in the log. There is
other similar error reported with TRIM and the SIL controller:
https://bugs.centos.org/view.php?id=5880
Apparently the controller doesn't support TRIM commands. This patch
disables TRIM support on the SATA SIL controller.
Because wakeups can (fundamentally) be late, a task might not be in
the expected state. Therefore testing against a task's state is racy,
and can yield false positives.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: oleg@redhat.com Fixes: 9067ac85d533 ("wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task") Link: http://lkml.kernel.org/r/1448933660-23082-1-git-send-email-sasha.levin@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
According to SJA1000 data sheet error-warning (EI) interrupt is not
cleared by setting the controller in to reset-mode.
Then if we have the following case:
- system is suspended (echo mem > /sys/power/state) and SJA1000 is left
in operating state
- A bus error condition occurs which activates EI interrupt, system is
still suspended which means EI interrupt will be not be handled nor
cleared.
If the above two events occur, on resume there is no way to return the
SJA1000 to operating state, except to cycle power to it.
By simply reading the IR register on start we will clear any previous
conditions that could be present.
Signed-off-by: Mirza Krak <mirza.krak@hostmobility.com> Reported-by: Christian Magnusson <Christian.Magnusson@semcon.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sasha's found a NULL pointer dereference in the RDS connection code when
sending a message to an apparently unbound socket. The problem is caused
by the code checking if the socket is bound in rds_sendmsg(), which checks
the rs_bound_addr field without taking a lock on the socket. This opens a
race where rs_bound_addr is temporarily set but where the transport is not
in rds_bind(), leading to a NULL pointer dereference when trying to
dereference 'trans' in __rds_conn_create().
Vegard wrote a reproducer for this issue, so kindly ask him to share if
you're interested.
I cannot reproduce the NULL pointer dereference using Vegard's reproducer
with this patch, whereas I could without.
Complete earlier incomplete fix to CVE-2015-6937:
74e98eb08588 ("RDS: verify the underlying transport exists before creating a connection")
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com> Reviewed-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When using call_rcu(), the called function may be delayed quite
significantly, and without a matching rcu_barrier() there's no
way to be sure it has finished.
Therefore, global state that could be gone/freed/reused should
never be touched in the callback.
Fix this in mesh by moving the atomic_dec() into the caller;
that's not really a problem since we already unlinked the path
and it will be destroyed anyway.
This fixes a crash Jouni observed when running certain tests in
a certain order, in which the mesh interface was torn down, the
memory reused for a function pointer (work struct) and running
that then crashed since the pointer had been decremented by 1,
resulting in an invalid instruction byte stream.
The virtio core uses a static ida named virtio_index_ida for
assigning index numbers to virtio devices during registration.
The ida core may allocate some internal idr cache layers and
an ida bitmap upon any ida allocation, and all these layers are
truely freed only upon the ida destruction. The virtio_index_ida
is not destroyed at present, leading to a memory leak when using
the virtio core as a module and atleast one virtio device is
registered and unregistered.
Fix this by invoking ida_destroy() in the virtio core module
exit.
Signed-off-by: Suman Anna <s-anna@ti.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Do not update the read stamp after swapping out the reader page from the
write buffer. If the reader page is swapped out of the buffer before an
event is written to it, then the read_stamp may get an out of date
timestamp, as the page timestamp is updated on the first commit to that
page.
rb_get_reader_page() only returns a page if it has an event on it, otherwise
it will return NULL. At that point, check if the page being returned has
events and has not been read yet. Then at that point update the read_stamp
to match the time stamp of the reader page.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following test program from Dmitry can cause softlockups or RCU
stalls as it copies 1GB from tmpfs into eventfd and we don't have any
scheduling point at that path in sendfile(2) implementation:
int r1 = eventfd(0, 0);
int r2 = memfd_create("", 0);
unsigned long n = 1<<30;
fallocate(r2, 0, 0, n);
sendfile(r1, r2, 0, n);
Add cond_resched() into __splice_from_pipe() to fix the problem.
CC: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes STAR 9000953410: "perf callgraph profiling causing RCU stalls"
| perf record -g -c 15000 -e cycles /sbin/hackbench
|
| INFO: rcu_preempt self-detected stall on CPU
| 1: (1 GPs behind) idle=609/140000000000002/0 softirq=2914/2915 fqs=603
| Task dump for CPU 1:
in-kernel dwarf unwinder has a fast binary lookup and a fallback linear
search (which iterates thru each of ~11K entries) thus takes 2 orders of
magnitude longer (~3 million cycles vs. 2000). Routines written in hand
assembler lack dwarf info (as we don't support assembler CFI pseudo-ops
yet) fail the unwinder binary lookup, hit linear search, failing
nevertheless in the end.
However the linear search is pointless as binary lookup tables are created
from it in first place. It is impossible to have binary lookup fail while
succeed the linear search. It is pure waste of cycles thus removed by
this patch.
This manifested as RCU stalls / NMI watchdog splat when running
hackbench under perf with callgraph profiling. The triggering condition
was perf counter overflowing in routine lacking dwarf info (like memset)
leading to patheic 3 million cycle unwinder slow path and by the time it
returned new interrupts were already pending (Timer, IPI) and taken
rightaway. The original memset didn't make forward progress, system kept
accruing more interrupts and more unwinder delayes in a vicious feedback
loop, ultimately triggering the NMI diagnostic.
If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single
512 byte sector would be read (secsize / 512). However the partition
structure would be located past the end of the buffer (secsize % 512).
Anytime a write operation is performed with Reliable Write flag enabled,
the eMMC device is enforced to bypass the cache and do a write to the
underling NVM device by Jedec specification; this causes a performance
penalty since write operations can't be optimized by the device cache.
In our tests, we replayed a typical mobile daily trace pattern and found
~9% overall time reduction in trace replay by using this patch. Also the
write ops within 4KB~64KB chunk size range get a 40~60% performance
improvement by using the patch (as this range of write chunks are the ones
affected by REQ_META).
This patch has been discussed in the Mobile & Embedded Linux Storage Forum
and it's the results of feedbacks from many people. We also checked with
fsdevl and f2fs mailing list developers that this change in the usage of
REQ_META is not affecting FS behavior and we got positive feedbacks.
Reporting here the feedbacks:
http://comments.gmane.org/gmane.linux.file-systems/97219
http://thread.gmane.org/gmane.linux.file-systems.f2fs/3178/focus=3183
Signed-off-by: Bruce Ford <bford@micron.com> Signed-off-by: Luca Porzio <lporzio@micron.com> Fixes: ce39f9d17c14 ("mmc: support packed write command for eMMC4.5 devices") Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is an issue on SMAP enabled CPUs and 32 bit apps running on 64 bit
OS. Do not access user memory from kernel code. The SMAP bit restricts
accessing user memory from kernel code.
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Do not use PAGE_SIZE marco to calculate max_sectors per I/O
request. Driver code assumes PAGE_SIZE will be always 4096 which can
lead to wrongly calculated value if PAGE_SIZE is not 4096. This issue
was reported in Ubuntu Bugzilla Bug #1475166.
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit 1c6c69525b40 ("genirq: Reject bogus threaded irq requests")
threaded IRQs without a primary handler need to be requested with
IRQF_ONESHOT, otherwise the request will fail.
scripts/coccinelle/misc/irqf_oneshot.cocci detected this issue.
Fixes: b5874f33bbaf ("wm831x_power: Use genirq") Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com> Signed-off-by: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The iomap[] array has PCIM_IOMAP_MAX (6) elements and not
DEVICE_COUNT_RESOURCE (16). This bug was found using a static checker.
It may be that the "if (!(mask & (1 << i)))" check means we never
actually go past the end of the array in real life.
projects / linux-stable / log