commit 017b1660df upstream.
The page migration code employs try_to_unmap() to try and unmap the source
page. This is accomplished by using rmap_walk to find all vmas where the
page is mapped. This search stops when page mapcount is zero. For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings. Shared mappings are tracked via the reference count of the PMD
page. Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.
This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page. Hence, data is lost.
This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors. DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages. A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.
To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages. If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page. After this, flush caches and TLB.
mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked. Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.
Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz@oracle.com: make _range_in_vma() a static inline]
Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c99 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported from 4.4 to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit c5510b8daf upstream.
If CONFIG_GPOILIB is not set, the stub of gpio_to_desc() should return
the same type of error as regular version: NULL. All the callers
compare the return value of gpio_to_desc() against NULL, so returned
ERR_PTR would be treated as non-error case leading to dereferencing of
error value.
Fixes: 79a9becda8 ("gpiolib: export descriptor-based GPIO interface")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit a28ebea2ad upstream.
KVM devices were manipulating list data structures without any form of
synchronization, and some implementations of the create operations also
suffered from a lack of synchronization.
Now when we've split the xics create operation into create and init, we
can hold the kvm->lock mutex while calling the create operation and when
manipulating the devices list.
The error path in the generic code gets slightly ugly because we have to
take the mutex again and delete the device from the list, but holding
the mutex during anon_inode_getfd or releasing/locking the mutex in the
common non-error path seemed wrong.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[bwh: Backported to 3.16:
- Drop change to a failure path that doesn't exist in kvm_vgic_create()
- Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 023e9fddc3 upstream.
As we are about to hold the kvm->lock during the create operation on KVM
devices, we should move the call to xics_debugfs_init into its own
function, since holding a mutex over extended amounts of time might not
be a good idea.
Introduce an init operation on the kvm_device_ops struct which cannot
fail and call this, if configured, after the device has been created.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 13054abbaa upstream.
Ring buffer implementation in hid_debug_event() and hid_debug_events_read()
is strange allowing lost or corrupted data. After commit 717adfdaf1
("HID: debug: check length before copy_to_user()") it is possible to enter
an infinite loop in hid_debug_events_read() by providing 0 as count, this
locks up a system. Fix this by rewriting the ring buffer implementation
with kfifo and simplify the code.
This fixes CVE-2019-3819.
v2: fix an execution logic and add a comment
v3: use __set_current_state() instead of set_current_state()
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1669187
Fixes: cd667ce247 ("HID: use debugfs for events/reports dumping")
Fixes: 717adfdaf1 ("HID: debug: check length before copy_to_user()")
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit d4b09acf92 upstream.
if node have NFSv41+ mounts inside several net namespaces
it can lead to use-after-free in svc_process_common()
svc_process_common()
/* Setup reply header */
rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE
svc_process_common() can use incorrect rqstp->rq_xprt,
its caller function bc_svc_process() takes it from serv->sv_bc_xprt.
The problem is that serv is global structure but sv_bc_xprt
is assigned per-netnamespace.
According to Trond, the whole "let's set up rqstp->rq_xprt
for the back channel" is nothing but a giant hack in order
to work around the fact that svc_process_common() uses it
to find the xpt_ops, and perform a couple of (meaningless
for the back channel) tests of xpt_flags.
All we really need in svc_process_common() is to be able to run
rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr()
Bruce J Fields points that this xpo_prep_reply_hdr() call
is an awfully roundabout way just to do "svc_putnl(resv, 0);"
in the tcp case.
This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(),
now it calls svc_process_common() with rqstp->rq_xprt = NULL.
To adjust reply header svc_process_common() just check
rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case.
To handle rqstp->rq_xprt = NULL case in functions called from
svc_process_common() patch intruduces net namespace pointer
svc_rqst->rq_bc_net and adjust SVC_NET() definition.
Some other function was also adopted to properly handle described case.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Fixes: 23c20ecd44 ("NFS: callback up - users counting cleanup")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
v2: - added lost extern svc_tcp_prep_reply_hdr()
- context changes in svc_process_common()
- dropped trace_svc_process() changes
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 67a2e213e7 upstream.
This was found during userspace fuzzing test when a large size dma cma
allocation is made by driver(like ion) through userspace.
show_stack+0x10/0x1c
dump_stack+0x74/0xc8
kasan_report_error+0x2b0/0x408
kasan_report+0x34/0x40
__asan_storeN+0x15c/0x168
memset+0x20/0x44
__dma_alloc_coherent+0x114/0x18c
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.16: cma_alloc() does not exist so only
dma_alloc_from_contiguous() needs to be changed]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 704620afc7 upstream.
When reading an extra descriptor, we need to properly check the minimum
and maximum size allowed, to prevent from invalid data being sent by a
device.
Reported-by: Hui Peng <benquike@gmail.com>
Reported-by: Mathias Payer <mathias.payer@nebelwelt.net>
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Mathias Payer <mathias.payer@nebelwelt.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0145b50566 upstream.
Before this commit sensor_hub_input_attr_get_raw_value() failed to take
the signedness of 16 and 8 bit values into account, returning e.g.
65436 instead of -100 for the z-axis reading of an accelerometer.
This commit adds a new is_signed parameter to the function and makes all
callers pass the appropriate value for this.
While at it, this commit also fixes up some neighboring lines where
statements were needlessly split over 2 lines to improve readability.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[bwh: Backported to 3.16:
- sensor_hub_input_attr_get_raw_value() doesn't take a sync/async flag
parameter
- In sensor_hub_input_attr_get_raw_value() keep using data->pending instead of
hsdev->pending
- In magn_3d_read_raw() keep using chan->scan_index intstead of chan->address
- Drop changes in hid-sensor-{custom,humidity,temperature}
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit a4310fa2f2 upstream.
This patch factors out all non sending parts of can_get_echo_skb() into
a seperate function __can_get_echo_skb(), so that it can be re-used in
an upcoming patch.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 781f0766cc upstream.
Devices connected under Terminus Technology Inc. Hub (1a40:0101) may
fail to work after the system resumes from suspend:
[ 206.063325] usb 3-2.4: reset full-speed USB device number 4 using xhci_hcd
[ 206.143691] usb 3-2.4: device descriptor read/64, error -32
[ 206.351671] usb 3-2.4: device descriptor read/64, error -32
Info for this hub:
T: Bus=03 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#= 2 Spd=480 MxCh= 4
D: Ver= 2.00 Cls=09(hub ) Sub=00 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=1a40 ProdID=0101 Rev=01.11
S: Product=USB 2.0 Hub
C: #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
Some expirements indicate that the USB devices connected to the hub are
innocent, it's the hub itself is to blame. The hub needs extra delay
time after it resets its port.
Hence wait for extra delay, if the device is connected to this quirky
hub.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16:
- Drop module parameter changes
- We don't have a USB_PORT_QUIRK_FAST_ENUM quirk]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 35b69a420b upstream.
Add support for platforms where pit_shutdown() doesn't work because of a
quirk in the PIT emulation. On these platforms setting the counter register
to zero causes the PIT to start running again, negating the shutdown.
Provide a global variable that controls whether the counter register is
zero'ed, which platform specific code can override.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>
Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Cc: "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>
Cc: "jgross@suse.com" <jgross@suse.com>
Cc: "akataria@vmware.com" <akataria@vmware.com>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>
Cc: "apw@canonical.com" <apw@canonical.com>
Cc: vkuznets <vkuznets@redhat.com>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>
Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Cc: KY Srinivasan <kys@microsoft.com>
Link: https://lkml.kernel.org/r/1541303219-11142-2-git-send-email-mikelley@microsoft.com
[bwh: Backported to 3.16:
- Don't use __ro_after_init
- Adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit b1d0a5d0cb upstream.
recent and hashlimit both create /proc files, but only check that
name is 0 terminated.
This can trigger WARN() from procfs when name is "" or "/".
Add helper for this and then use it for both.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: <syzbot+0502b00edac2a0680b61@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[bwh: Backported to 3.16:
- xt_hashlimit has only one check function
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 36156f9241 upstream.
Add of_get_compatible_child() helper that can be used to lookup
compatible child nodes.
Several drivers currently use of_find_compatible_node() to lookup child
nodes while failing to notice that the of_find_ functions search the
entire tree depth-first (from a given start node) and therefore can
match unrelated nodes. The fact that these functions also drop a
reference to the node they start searching from (e.g. the parent node)
is typically also overlooked, something which can lead to use-after-free
bugs.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 94e6992bb5 upstream.
If the read is large enough, we end up spinning in the messenger:
libceph: osd0 192.168.122.1:6801 io error
libceph: osd0 192.168.122.1:6801 io error
libceph: osd0 192.168.122.1:6801 io error
This is a receive side limit, so only reads were affected.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit bd7e5b0899 upstream.
The FPU is always active now when running KVM.
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16:
- eagerfpu is still optional (but enabled by default) so disable KVM if
eagerfpu is disabled
- Remove one additional use of KVM_REQ_DEACTIVATE_FPU which was
removed earlier upstream in commit c592b57347
"x86/fpu: Remove use_eager_fpu()"
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 78c9c4dfbf upstream.
The posix timer overrun handling is broken because the forwarding functions
can return a huge number of overruns which does not fit in an int. As a
consequence timer_getoverrun(2) and siginfo::si_overrun can turn into
random number generators.
The k_clock::timer_forward() callbacks return a 64 bit value now. Make
k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal
accounting is correct. 3Remove the temporary (int) casts.
Add a helper function which clamps the overrun value returned to user space
via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value
between 0 and INT_MAX. INT_MAX is an indicator for user space that the
overrun value has been clamped.
Reported-by: Team OWL337 <icytxw@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de
[bwh: Backported to 3.16: adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 9bd616e3db upstream.
The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
enabled. Commit c8cc7d4de7 ("sched/idle: Reorganize the idle loop")
removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
compiler optimising away __this_cpu_read(cpuidle_devices). However, with
CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
and the kernel fails to link since cpuidle_devices is not defined.
This patch introduces an accessor function for the current CPU cpuidle
device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
cpuidle_idle_call().
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit af7d6cce53 upstream.
Since commit 5aad1de5ea ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.
As Stefano described in commit e9fa1495d7 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
- if the local MTU is now lower than the PMTU, that PMTU is now
incorrect
- if the local MTU was the lowest value in the path, and is increased,
we might discover a higher PMTU
Similarly to what commit e9fa1495d7 did for IPv6, update PMTU in those
cases.
If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.
To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.
Fixes: 5aad1de5ea ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16:
- Pass net_device argument to call_netdevice_notifiers_info()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 34dbbcdbf6 upstream.
A lot of seqfile users seem to be using things like %pK that uses the
credentials of the current process, but that is actually completely
wrong for filesystem interfaces.
The unix semantics for permission checking files is to check permissions
at _open_ time, not at read or write time, and that is not just a small
detail: passing off stdin/stdout/stderr to a suid application and making
the actual IO happen in privileged context is a classic exploit
technique.
So if we want to be able to look at permissions at read time, we need to
use the file open credentials, not the current ones. Normal file
accesses can just use "f_cred" (or any of the helper functions that do
that, like file_ns_capable()), but the seqfile interfaces do not have
any such options.
It turns out that seq_file _does_ save away the user_ns information of
the file, though. Since user_ns is just part of the full credential
information, replace that special case with saving off the cred pointer
instead, and suddenly seq_file has all the permission information it
needs.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 6fb650d43d upstream.
When a USB driver is bound to an interface (either through probing or
by claiming it) or is unbound from an interface, the USB core always
disables Link Power Management during the transition and then
re-enables it afterward. The reason is because the driver might want
to prevent hub-initiated link power transitions, in which case the HCD
would have to recalculate the various LPM parameters. This
recalculation takes place when LPM is re-enabled and the new
parameters are sent to the device and its parent hub.
However, if the driver does not want to prevent hub-initiated link
power transitions then none of this work is necessary. The parameters
don't need to be recalculated, and LPM doesn't need to be disabled and
re-enabled.
It turns out that disabling and enabling LPM can be time-consuming,
enough so that it interferes with user programs that want to claim and
release interfaces rapidly via usbfs. Since the usbfs kernel driver
doesn't set the disable_hub_initiated_lpm flag, we can speed things up
and get the user programs to work by leaving LPM alone whenever the
flag isn't set.
And while we're improving the way disable_hub_initiated_lpm gets used,
let's also fix its kerneldoc.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Matthew Giassa <matthew@giassa.net>
CC: Mathias Nyman <mathias.nyman@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0daf434940 upstream.
Add a small skb_mac_header_len() helper similarly as the
skb_network_header_len() we have and replace open coded
places in BPF's bpf_skb_change_proto() helper. Will also
be used in upcoming work.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: drop changes in bpf]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 80188b0d77 upstream.
XFS uses non-stanard batch sizes for avoiding frequent global
counter updates on it's allocated inode counters, as they increment
or decrement in batches of 64 inodes. Hence the standard percpu
counter batch of 32 means that the counter is effectively a global
counter. Currently Xfs uses a batch size of 128 so that it doesn't
take the global lock on every single modification.
However, Xfs also needs to compare accurately against zero, which
means we need to use percpu_counter_compare(), and that has a
hard-coded batch size of 32, and hence will spuriously fail to
detect when it is supposed to use precise comparisons and hence
the accounting goes wrong.
Add __percpu_counter_compare() to take a custom batch size so we can
use it sanely in XFS and factor percpu_counter_compare() to use it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 2afc9166f7 upstream.
Introduce these two functions and export them such that the next patch
can add calls to these functions from the SCSI core.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 359f642700 upstream.
This allows bio_integrity_bytes() to be called from drivers instead of
open coding it.
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Edwards <gedwards@ddn.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[bwh: Backported to 3.16: bio_integrity_intervals() was called
bio_integrity_hw_sectors() and had a different implementation. Move it
without renaming.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit b18cb64ead upstream.
This reverts more of:
b76437579d ("procfs: mark thread stack correctly in proc/<pid>/maps")
... which was partially reverted by:
65376df582 ("proc: revert /proc/<pid>/maps [stack:TID] annotation")
Originally, /proc/PID/task/TID/maps was the same as /proc/TID/maps.
In current kernels, /proc/PID/maps (or /proc/TID/maps even for
threads) shows "[stack]" for VMAs in the mm's stack address range.
In contrast, /proc/PID/task/TID/maps uses KSTK_ESP to guess the
target thread's stack's VMA. This is racy, probably returns garbage
and, on arches with CONFIG_TASK_INFO_IN_THREAD=y, is also crash-prone:
KSTK_ESP is not safe to use on tasks that aren't known to be running
ordinary process-context kernel code.
This patch removes the difference and just shows "[stack]" for VMAs
in the mm's stack range. This is IMO much more sensible -- the
actual "stack" address really is treated specially by the VM code,
and the current thread stack isn't even well-defined for programs
that frequently switch stacks on their own.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/3e678474ec14e0a0ec34c611016753eea2e1b8ba.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16: Squash in the earlier commits 58cb65487e
"proc/maps: make vm_is_stack() logic namespace-friendly" and
65376df582 "proc: revert /proc/<pid>/maps [stack:TID] annotation",
which would introduce build failures if applied separately.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit a528aca7f3 upstream.
Games with ordering and barriers are way too brittle. Just
bump ->d_seq before and after updating ->d_inode and ->d_flags
type bits, so that verifying ->d_seq would guarantee they are
coherent.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 4bf46a2726 upstream.
Impose ordering on accesses of d_inode and d_flags to avoid the need to do
this:
if (!dentry->d_inode || d_is_negative(dentry)) {
when this:
if (d_is_negative(dentry)) {
should suffice.
This check is especially problematic if a dentry can have its type field set
to something other than DENTRY_MISS_TYPE when d_inode is NULL (as in
unionmount).
What we really need to do is stick a write barrier between setting d_inode and
setting d_flags and a read barrier between reading d_flags and reading
d_inode.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.16:
- Use ACCESS_ONCE() instead of {READ,WRITE}_ONCE()
- There's no DCACHE_FALLTHRU flag]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 73c8d89455 upstream.
Maintain the tracing on/off setting of the ring_buffer when switching
to the trace buffer snapshot.
Taking a snapshot is done by swapping the backup ring buffer
(max_tr_buffer). But since the tracing on/off setting is defined
by the ring buffer, when swapping it, the tracing on/off setting
can also be changed. This causes a strange result like below:
/sys/kernel/debug/tracing # cat tracing_on
1
/sys/kernel/debug/tracing # echo 0 > tracing_on
/sys/kernel/debug/tracing # cat tracing_on
0
/sys/kernel/debug/tracing # echo 1 > snapshot
/sys/kernel/debug/tracing # cat tracing_on
1
/sys/kernel/debug/tracing # echo 1 > snapshot
/sys/kernel/debug/tracing # cat tracing_on
0
We don't touch tracing_on, but snapshot changes tracing_on
setting each time. This is an anomaly, because user doesn't know
that each "ring_buffer" stores its own tracing-enable state and
the snapshot is done by swapping ring buffers.
Link: http://lkml.kernel.org/r/153149929558.11274.11730609978254724394.stgit@devbox
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Hiraku Toyooka <hiraku.toyooka@cybertrust.co.jp>
Fixes: debdd57f51 ("tracing: Make a snapshot feature available from userspace")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
[ Updated commit log and comment in the code ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit bac78aabcf upstream.
The handling of can error states is different between platforms.
This is an attempt to correct that problem.
I've moved this handling into a generic function for changing the
error state. This ensures that error state changes are handled
the same way everywhere (where this function is used).
This new mechanism also adds reverse state transitioning in error
frames, i.e. the user will be notified through the socket interface
when the state goes down.
Signed-off-by: Andri Yngvason <andri.yngvason@marel.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This was done as part of commit 08a77676f9 upstream, from which
the following description is taken:
> strlcpy() is worse than strlcpy() because it unconditionally runs
> strlen() on the source string, and the only reason we switched to
> strlcpy() here was because it was lacking __must_check, which doesn't
> reflect any material differences between the two function. It's just
> that someone added __must_check to strscpy() and not to strlcpy().
>
> These basic string copy operations are used in variety of ways, and
> one of not-so-uncommon use cases is safely handling truncated copies,
> where the caller naturally doesn't care about the return value. The
> __must_check doesn't match the actual use cases and forces users to
> opt for inferior variants which lack __must_check by happenstance or
> spread ugly (void) casts.
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 240630e618 upstream.
There have been several reports of LPM related hard freezes about once
a day on multiple Lenovo 50 series models. Strange enough these reports
where not disk model specific as LPM issues usually are and some users
with the exact same disk + laptop where seeing them while other users
where not seeing these issues.
It turns out that enabling LPM triggers a firmware bug somewhere, which
has been fixed in later BIOS versions.
This commit adds a new ahci_broken_lpm() function and a new ATA_FLAG_NO_LPM
for dealing with this.
The ahci_broken_lpm() function contains DMI match info for the 4 models
which are known to be affected by this and the DMI BIOS date field for
known good BIOS versions. If the BIOS date is older then the one in the
table LPM will be disabled and a warning will be printed.
Note the BIOS dates are for known good versions, some older versions may
work too, but we don't know for sure, the table is using dates from BIOS
versions for which users have confirmed that upgrading to that version
makes the problem go away.
Unfortunately I've been unable to get hold of the reporter who reported
that BIOS version 2.35 fixed the problems on the W541 for him. I've been
able to verify the DMI_SYS_VENDOR and DMI_PRODUCT_VERSION from an older
dmidecode, but I don't know the exact BIOS date as reported in the DMI.
Lenovo keeps a changelog with dates in their release notes, but the
dates there are the release dates not the build dates which are in DMI.
So I've chosen to set the date to which we compare to one day past the
release date of the 2.34 BIOS. I plan to fix this with a follow up
commit once I've the necessary info.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 15bfd21fbc upstream.
A device may have boundary restrictions where the number of sectors
between boundaries exceeds its max transfer size. In this case, we need
to cap the max size to the smaller of the two limits.
Reported-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Tested-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit ae4b884fc6 upstream.
sparse says:
fs/nfsd/auth.c:31:38: warning: incorrect type in argument 1 (different address spaces)
fs/nfsd/auth.c:31:38: expected struct cred const *cred
fs/nfsd/auth.c:31:38: got struct cred const [noderef] <asn:4>*real_cred
Add a new accessor for the ->real_cred and use that to fetch the
pointer. Accessing current->real_cred directly is actually quite safe
since we know that they can't go away so this is mostly a cosmetic fixup
to silence sparse.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit d5318d302e upstream.
Two framebuffer device-node names were looked up during probe, but were
only used as flags to indicate the presence of two framebuffer device.
Drop the unused framebuffer name along with a likewise unused device
pointer from the driver data, and update the platform data to pass in
booleans instead of the framebuffer strings. This allows us do drop the
node references acquired during probe, which would otherwise leak.
Note that there are no other in-kernel users of the modified
platform-data fields.
Fixes: 59eb2b5e57 ("drivers/video/backlight/as3711_bl.c: add OF support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 2026d35741 upstream.
The function __builtin_expect returns long type (see the gcc
documentation), and so do macros likely and unlikely. Unfortunatelly, when
CONFIG_PROFILE_ANNOTATED_BRANCHES is selected, the macros likely and
unlikely expand to __branch_check__ and __branch_check__ truncates the
long type to int. This unintended truncation may cause bugs in various
kernel code (we found a bug in dm-writecache because of it), so it's
better to fix __branch_check__ to return long.
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1805300818140.24812@file01.intranet.prod.int.rdu2.redhat.com
Cc: Ingo Molnar <mingo@redhat.com>
Fixes: 1f0d69a9fc ("tracing: profile likely and unlikely annotations")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit a1150c2022 upstream.
When hw and sw events are mixed in the same group, they are all attached
to the hw perf_event_context. This sometimes requires moving group of
perf_event to a different context.
We found a bug in how the kernel handles this, for example if we do:
perf stat -e '{faults,ref-cycles,faults}' -I 1000
1.005591180 1,297 faults
1.005591180 457,476,576 ref-cycles
1.005591180 <not supported> faults
First, sw event "faults" is attached to the sw context, and becomes the
group leader. Then, hw event "ref-cycles" is attached, so both events
are moved to the hw context. Last, another sw "faults" tries to attach,
but it fails because of mismatch between the new target ctx (from sw
pmu) and the group_leader's ctx (hw context, same as ref-cycles).
The broken condition is:
group_leader is sw event;
group_leader is on hw context;
add a sw event to the group.
Fix this scenario by checking group_leader's context (instead of just
event type). If group_leader is on hw context, use the ->pmu of this
context to look up context for the new event.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: b04243ef70 ("perf: Complete software pmu grouping")
Link: http://lkml.kernel.org/r/20180503194716.162815-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0c8e3fe35d upstream.
Needed by ext4 to test frozen fs before updating s_last_mounted.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 474c90156c upstream.
gcc-7 has an "optimization" pass that completely screws up, and
generates the code expansion for the (impossible) case of calling
ilog2() with a zero constant, even when the code gcc compiles does not
actually have a zero constant.
And we try to generate a compile-time error for anybody doing ilog2() on
a constant where that doesn't make sense (be it zero or negative). So
now gcc7 will fail the build due to our sanity checking, because it
created that constant-zero case that didn't actually exist in the source
code.
There's a whole long discussion on the kernel mailing about how to work
around this gcc bug. The gcc people themselevs have discussed their
"feature" in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785
but it's all water under the bridge, because while it looked at one
point like it would be solved by the time gcc7 was released, that was
not to be.
So now we have to deal with this compiler braindamage.
And the only simple approach seems to be to just delete the code that
tries to warn about bad uses of ilog2().
So now "ilog2()" will just return 0 not just for the value 1, but for
any non-positive value too.
It's not like I can recall anybody having ever actually tried to use
this function on any invalid value, but maybe the sanity check just
meant that such code never made it out in public.
Reported-by: Laura Abbott <labbott@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>,
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.16: There's only one log2.h file]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 30035e4575 upstream.
The strscpy() API is intended to be used instead of strlcpy(),
and instead of most uses of strncpy().
- Unlike strlcpy(), it doesn't read from memory beyond (src + size).
- Unlike strlcpy() or strncpy(), the API provides an easy way to check
for destination buffer overflow: an -E2BIG error return value.
- The provided implementation is robust in the face of the source
buffer being asynchronously changed during the copy, unlike the
current implementation of strlcpy().
- Unlike strncpy(), the destination buffer will be NUL-terminated
if the string in the source buffer is too long.
- Also unlike strncpy(), the destination buffer will not be updated
beyond the NUL termination, avoiding strncpy's behavior of zeroing
the entire tail end of the destination buffer. (A memset() after
the strscpy() can be used if this behavior is desired.)
- The implementation should be reasonably performant on all
platforms since it uses the asm/word-at-a-time.h API rather than
simple byte copy. Kernel-to-kernel string copy is not considered
to be performance critical in any case.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0b3225ab94 upstream.
Mixed mode allows a kernel built for x86_64 to interact with 32-bit
EFI firmware, but requires us to define all struct definitions carefully
when it comes to pointer sizes.
'struct efi_pci_io_protocol_32' currently uses a 'void *' for the
'romimage' field, which will be interpreted as a 64-bit field
on such kernels, potentially resulting in bogus memory references
and subsequent crashes.
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180504060003.19618-13-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 1e2e547a93 upstream.
For anything NFS-exported we do _not_ want to unlock new inode
before it has grown an alias; original set of fixes got the
ordering right, but missed the nasty complication in case of
lockdep being enabled - unlock_new_inode() does
lockdep_annotate_inode_mutex_key(inode)
which can only be done before anyone gets a chance to touch
->i_mutex. Unfortunately, flipping the order and doing
unlock_new_inode() before d_instantiate() opens a window when
mkdir can race with open-by-fhandle on a guessed fhandle, leading
to multiple aliases for a directory inode and all the breakage
that follows from that.
Correct solution: a new primitive (d_instantiate_new())
combining these two in the right order - lockdep annotate, then
d_instantiate(), then the rest of unlock_new_inode(). All
combinations of d_instantiate() with unlock_new_inode() should
be converted to that.
Tested-by: Mike Marshall <hubcap@omnibond.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.16:
- Drop changes in orangefs
- Apply similar change to ext3
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 24a7e4d207 upstream.
For cleanup it's helpful to be able to simply scan all vqs and discard
all data. Add an iterator to do that.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 6510bbc88e upstream.
Currently it is possible to read and/or write to suspend EB's.
Writing /dev/mtdX or /dev/mtdblockX from several processes may
break the flash state machine.
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 903f9db10f upstream.
syzbot is reporting kernel panic [1] triggered by memory allocation failure
at tty_ldisc_get() from tty_ldisc_init(). But since both tty_ldisc_get()
and caller of tty_ldisc_init() can cleanly handle errors, tty_ldisc_init()
does not need to call panic() when tty_ldisc_get() failed.
[1] https://syzkaller.appspot.com/bug?id=883431818e036ae6a9981156a64b821110f39187
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 2c964a2f41 upstream.
The two functions alloc_tty_struct and initialize_tty_struct are
always called together. Merge them into alloc_tty_struct, updating its
prototype and the only two callers of these functions.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit c043ec1ca5 upstream.
Currently, we use int for buffer length and bytes_per_datum. However,
kfifo uses unsigned int for length and size_t for element size. We need
to make sure these matches or we will have bugs related to overflow (in
the range between INT_MAX and UINT_MAX for length, for example).
In addition, set_bytes_per_datum uses size_t while bytes_per_datum is an
int, which would cause bugs for large values of bytes_per_datum.
Change buffer length to use unsigned int and bytes_per_datum to use
size_t.
Signed-off-by: Martin Kelly <mkelly@xevo.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[bwh: Backported to 3.16:
- Drop change in iio_dma_buffer_set_length()
- Adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 39a4940eaa upstream.
Today msg_lspid and msg_lrpid are remembered in the pid namespace of
the creator and the processes that last send or received a sysvipc
message. If you have processes in multiple pid namespaces that is
just wrong. The process ids reported will not make the least bit of
sense.
This fix is slightly more susceptible to a performance problem than
the related fix for System V shared memory. By definition the pids
are updated by msgsnd and msgrcv, the fast path of System V message
queues. The only concern over the previous implementation is the
incrementing and decrementing of the pid reference count. As that is
the only difference and multiple updates by of the task_tgid by
threads in the same process have been shown in af_unix sockets to
create a cache line ping-pong between cpus of the same processor.
In this case I don't expect cache lines holding pid reference counts
to ping pong between cpus. As senders and receivers update different
pids there is a natural separation there. Further if multiple threads
of the same process either send or receive messages the pid will be
updated to the same value and ipc_update_pid will avoid the reference
count update.
Which means in the common case I expect msg_lspid and msg_lrpid to
remain constant, and reference counts not to be updated when messages
are sent.
In rare cases it may be possible to trigger the issue which was
observed for af_unix sockets, but it will require multiple processes
with multiple threads to be either sending or receiving messages. It
just does not feel likely that anyone would do that in practice.
This change updates msgctl(..., IPC_STAT, ...) to return msg_lspid and
msg_lrpid in the pid namespace of the process calling stat.
This change also updates cat /proc/sysvipc/msg to return print msg_lspid
and msg_lrpid in the pid namespace of the process that opened the proc
file.
Fixes: b488893a39 ("pid namespaces: changes to show virtual ids to user")
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 98f929b1bd upstream.
Today shm_cpid and shm_lpid are remembered in the pid namespace of the
creator and the processes that last touched a sysvipc shared memory
segment. If you have processes in multiple pid namespaces that
is just wrong, and I don't know how this has been over-looked for
so long.
As only creation and shared memory attach and shared memory detach
update the pids I do not expect there to be a repeat of the issues
when struct pid was attached to each af_unix skb, which in some
notable cases cut the performance in half. The problem was threads of
the same process updating same struct pid from different cpus causing
the cache line to be highly contended and bounce between cpus.
As creation, attach, and detach are expected to be rare operations for
sysvipc shared memory segments I do not expect that kind of cache line
ping pong to cause probems. In addition because the pid is at a fixed
location in the structure instead of being dynamic on a skb, the
reference count of the pid does not need to be updated on each
operation if the pid is the same. This ability to simply skip the pid
reference count changes if the pid is unchanging further reduces the
likelihood of the a cache line holding a pid reference count
ping-ponging between cpus.
Fixes: b488893a39 ("pid namespaces: changes to show virtual ids to user")
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
