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There is existing use after free bug when deferred struct pages are
enabled:
The memblock_add() allocates memory for the memory array if more than
128 entries are needed. See comment in e820__memblock_setup():
* The bootstrap memblock region count maximum is 128 entries
* (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
* than that - so allow memblock resizing.
This memblock memory is freed here:
free_low_memory_core_early()
We access the freed memblock.memory later in boot when deferred pages
are initialized in this path:
deferred_init_memmap()
for_each_mem_pfn_range()
__next_mem_pfn_range()
type = &memblock.memory;
One possible explanation for why this use-after-free hasn't been hit
before is that the limit of INIT_MEMBLOCK_REGIONS has never been
exceeded at least on systems where deferred struct pages were enabled.
Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128,
and verifying in qemu that this code is getting excuted and that the
freed pages are sane.
Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com
Fixes: 7e18adb4f80b ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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These are the few pending fixes I have queued up for v4.13-final. One
is a a generic regression fix for recursive loops on kmod and the other
one is a trivial print out correction.
During the v4.13 development we assumed that recursive kmod loops were
no longer possible. Clearly that is not true. The regression fix makes
use of a new killable wait. We use a killable wait to be paranoid in
how signals might be sent to modprobe and only accept a proper SIGKILL.
The signal will only be available to userspace to issue *iff* a thread
has already entered a wait state, and that happens only if we've already
throttled after 50 kmod threads have been hit.
Note that although it may seem excessive to trigger a failure afer 5
seconds if all kmod thread remain busy, prior to the series of changes
that went into v4.13 we would actually *always* fatally fail any request
which came in if the limit was already reached. The new waiting
implemented in v4.13 actually gives us *more* breathing room -- the wait
for 5 seconds is a wait for *any* kmod thread to finish. We give up and
fail *iff* no kmod thread has finished and they're *all* running
straight for 5 consecutive seconds. If 50 kmod threads are running
consecutively for 5 seconds something else must be really bad.
Recursive loops with kmod are bad but they're also hard to implement
properly as a selftest without currently fooling current userspace tools
like kmod [1]. For instance kmod will complain when you run depmod if
it finds a recursive loop with symbol dependency between modules as such
this type of recursive loop cannot go upstream as the modules_install
target will fail after running depmod.
These tests already exist on userspace kmod upstream though (refer to
the testsuite/module-playground/mod-loop-*.c files). The same is not
true if request_module() is used though, or worst if aliases are used.
Likewise the issue with 64-bit kernels booting 32-bit userspace without
a binfmt handler built-in is also currently not detected and proactively
avoided by userspace kmod tools, or kconfig for all architectures.
Although we could complain in the kernel when some of these individual
recursive issues creep up, proactively avoiding these situations in
userspace at build time is what we should keep striving for.
Lastly, since recursive loops could happen with kmod it may mean
recursive loops may also be possible with other kernel usermode helpers,
this should be investigated and long term if we can come up with a more
sensible generic solution even better!
[0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20170809-kmod-for-v4.13-final
[1] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git
This patch (of 3):
This wait is similar to wait_event_interruptible_timeout() but only
accepts SIGKILL interrupt signal. Other signals are ignored.
Link: http://lkml.kernel.org/r/20170809234635.13443-2-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Matt Redfearn <matt.redfearn@imgetc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jaegeuk and Brad report a NULL pointer crash when writeback ending tries
to update the memcg stats:
BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0
IP: test_clear_page_writeback+0x12e/0x2c0
[...]
RIP: 0010:test_clear_page_writeback+0x12e/0x2c0
Call Trace:
<IRQ>
end_page_writeback+0x47/0x70
f2fs_write_end_io+0x76/0x180 [f2fs]
bio_endio+0x9f/0x120
blk_update_request+0xa8/0x2f0
scsi_end_request+0x39/0x1d0
scsi_io_completion+0x211/0x690
scsi_finish_command+0xd9/0x120
scsi_softirq_done+0x127/0x150
__blk_mq_complete_request_remote+0x13/0x20
flush_smp_call_function_queue+0x56/0x110
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x27/0x40
call_function_single_interrupt+0x89/0x90
RIP: 0010:native_safe_halt+0x6/0x10
(gdb) l *(test_clear_page_writeback+0x12e)
0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619).
614 mod_node_page_state(page_pgdat(page), idx, val);
615 if (mem_cgroup_disabled() || !page->mem_cgroup)
616 return;
617 mod_memcg_state(page->mem_cgroup, idx, val);
618 pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
619 this_cpu_add(pn->lruvec_stat->count[idx], val);
620 }
621
622 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
623 gfp_t gfp_mask,
The issue is that writeback doesn't hold a page reference and the page
might get freed after PG_writeback is cleared (and the mapping is
unlocked) in test_clear_page_writeback(). The stat functions looking up
the page's node or zone are safe, as those attributes are static across
allocation and free cycles. But page->mem_cgroup is not, and it will
get cleared if we race with truncation or migration.
It appears this race window has been around for a while, but less likely
to trigger when the memcg stats were updated first thing after
PG_writeback is cleared. Recent changes reshuffled this code to update
the global node stats before the memcg ones, though, stretching the race
window out to an extent where people can reproduce the problem.
Update test_clear_page_writeback() to look up and pin page->mem_cgroup
before clearing PG_writeback, then not use that pointer afterward. It
is a partial revert of 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
but leaves the pageref-holding callsites that aren't affected alone.
Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org
Fixes: 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Jaegeuk Kim <jaegeuk@kernel.org>
Tested-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reported-by: Bradley Bolen <bradleybolen@gmail.com>
Tested-by: Brad Bolen <bradleybolen@gmail.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> [4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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next/drivers
Pull "Reset controller changes for v4.14" from Philipp Zabel:
- constify zx2967 reset_ops
- add a convenience API to manage an array of resets
- let deassert report success and let assert report success for shared resets
if the reset controller driver does not implement (de)assert.
- add HSDKv1 reset driver
- remove Gemini reset controller, the driver is made obsolete
by a combined clock/reset driver in drivers/clk
- fix the total number of reset lines in the sunxi driver
- various uniphier updates and fixes:
- remove sLD3 SoC support
- simplify system reset register and bit definitions
- add audio systems, video input subsystem, and analog amplifiers reset
controls
* tag 'reset-for-4.14' of git://git.pengutronix.de/git/pza/linux:
reset: uniphier: add analog amplifiers reset control
reset: uniphier: add video input subsystem reset control
reset: uniphier: add audio systems reset control
reset: sunxi: fix number of reset lines
reset: uniphier: do not use per-SoC macro for system reset block
reset: uniphier: remove sLD3 SoC support
Revert "reset: Add a Gemini reset controller"
ARC: reset: introduce HSDKv1 reset driver
reset: make (de)assert report success for self-deasserting reset drivers
reset: Add APIs to manage array of resets
reset: zx2967: constify zx2967_reset_ops.
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next/drivers
Pull "arm: mediatek: soc updates for v4.14" from Matthias Brugger:
- add mt7623a smp support
- scpsys: reduce code duplication
- scpsys: add mt7622 support
- pmic wrapper: make of_device_ids constant
* tag 'v4.13-next-soc' of https://github.com/mbgg/linux-mediatek:
soc: mediatek: add SCPSYS power domain driver for MediaTek MT7622 SoC
soc: mediatek: add header files required for MT7622 SCPSYS dt-binding
soc: mediatek: reduce code duplication of scpsys_probe across all SoCs
dt-bindings: soc: update the binding document for SCPSYS on MediaTek MT7622 SoC
soc: mtk-pmic-wrap: make of_device_ids const.
ARM: mediatek: add MT7623a smp bringup code
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This further reduces contention with the transport_lock, and allows us
to convert to using a non-bh-safe spinlock, since the list is now never
accessed from a bh context.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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Conflicts:
drivers/infiniband/core/iwcm.c - The rdma_netlink patches in
HEAD and the iwarp cm workqueue fix (don't use WQ_MEM_RECLAIM,
we aren't safe for that context) touched the same code.
Signed-off-by: Doug Ledford <dledford@redhat.com>
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Some drivers (specifically the nes IB driver), want to create a lot of
sysfs driver attributes. Instead of open-coding the creation and
removal of these files (and getting it wrong btw), it's a better idea to
let the driver core handle all of this logic for us.
So add a new field to the pci driver structure, **groups, that allows
pci drivers to specify an attribute group list it wishes to have created
when it is registered with the driver core.
Big bonus is now the driver doesn't race with userspace when the sysfs
files are created vs. when the kobject is announced, so any script/tool
that actually wanted to use these files will not have to poll waiting
for them to show up.
Cc: Faisal Latif <faisal.latif@intel.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
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Add an API to get "pci_epf_device_id" matching the EPF name. This can be
used by the EPF driver to get the driver data corresponding to the EPF
device name.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
[bhelgaas: folded in "while" loop termination fix from Colin Ian King
<colin.king@canonical.com>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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A new mount option "cpuset_v2_mode" is added to the v1 cgroupfs
filesystem to enable cpuset controller to use v2 behavior in a v1
cgroup. This mount option applies only to cpuset controller and have
no effect on other controllers.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Since blk_mq_ops.reinit_request is only called from inside
blk_mq_reinit_tagset(), make this function pointer an argument of
blk_mq_reinit_tagset() instead of a member of struct blk_mq_ops.
This patch does not change any functionality but makes
blk_mq_reinit_tagset() calls easier to read and to analyze.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: James Smart <james.smart@broadcom.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The hardlockup detector on x86 uses a performance counter based on unhalted
CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the
performance counter period, so the hrtimer should fire 2-3 times before the
performance counter NMI fires. The NMI code checks whether the hrtimer
fired since the last invocation. If not, it assumess a hard lockup.
The calculation of those periods is based on the nominal CPU
frequency. Turbo modes increase the CPU clock frequency and therefore
shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x
nominal frequency) the perf/NMI period is shorter than the hrtimer period
which leads to false positives.
A simple fix would be to shorten the hrtimer period, but that comes with
the side effect of more frequent hrtimer and softlockup thread wakeups,
which is not desired.
Implement a low pass filter, which checks the perf/NMI period against
kernel time. If the perf/NMI fires before 4/5 of the watchdog period has
elapsed then the event is ignored and postponed to the next perf/NMI.
That solves the problem and avoids the overhead of shorter hrtimer periods
and more frequent softlockup thread wakeups.
Fixes: 58687acba592 ("lockup_detector: Combine nmi_watchdog and softlockup detector")
Reported-and-tested-by: Kan Liang <Kan.liang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dzickus@redhat.com
Cc: prarit@redhat.com
Cc: ak@linux.intel.com
Cc: babu.moger@oracle.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: acme@redhat.com
Cc: stable@vger.kernel.org
Cc: atomlin@redhat.com
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos
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Merge the flow handlers and irq domain extensions which are in a separate
branch so they can be consumed by the gpio folks.
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For an already existing irqdomain hierarchy, as might be obtained via
a call to pci_enable_msix_range(), a PCI driver wishing to add an
additional irqdomain to the hierarchy needs to be able to insert the
irqdomain to that already initialized hierarchy. Calling
irq_domain_create_hierarchy() allows the new irqdomain to be created,
but no existing code allows for initializing the associated irq_data.
Add a couple of helper functions (irq_domain_push_irq() and
irq_domain_pop_irq()) to initialize the irq_data for the new
irqdomain added to an existing hierarchy.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/1503017616-3252-6-git-send-email-david.daney@cavium.com
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Follow-on patch for gpio-thunderx uses a irqdomain hierarchy which
requires slightly different flow handlers, add them to chip.c which
contains most of the other flow handlers. Make these conditionally
compiled based on CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/1503017616-3252-3-git-send-email-david.daney@cavium.com
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Just because CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK is selected
doesn't mean that all the interrupts are using the effective
affinity mask. For a number of them, this mask is likely to
be empty.
In order to deal with this, let's restrict the use of the
effective affinity mask to these interrupts that have a non empty
effective affinity.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Link: http://lkml.kernel.org/r/20170818083925.10108-2-marc.zyngier@arm.com
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We need the ASM_UNREACHABLE() macro for a dependent patch.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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For SoC to achieve its lowest power platform idle state a set of hardware
preconditions must be met. These preconditions or constraints can be
obtained by issuing a device specific method (_DSM) with function "1".
Refer to the document provided in the link below.
Here during initialization (from attach() callback of LPS0 device), invoke
function 1 to get the device constraints. Each enabled constraint is
stored in a table.
The devices in this table are used to check whether they were in required
minimum state, while entering suspend. This check is done from platform
freeze wake() callback, only when /sys/power/pm_debug_messages attribute
is non zero.
If any constraint is not met and device is ACPI power managed then it
prints the device information to kernel logs.
Also if debug is enabled in acpi/sleep.c, the constraint table and state
of each device on wake is dumped in kernel logs.
Since pm_debug_messages_on setting is used as condition to check
constraints outside kernel/power/main.c, pm_debug_messages_on is changed
to a global variable.
Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This reverts commit 68c4a4f8abc60c9440ede9cd123d48b78325f7a3, with
various conflict clean-ups.
The capability check required too much privilege compared to simple DAC
controls. A system builder was forced to have crash handler processes
run with CAP_SYSLOG which would give it the ability to read (and wipe)
the _current_ dmesg, which is much more access than being given access
only to the historical log stored in pstorefs.
With the prior commit to make the root directory 0750, the files are
protected by default but a system builder can now opt to give access
to a specific group (via chgrp on the pstorefs root directory) without
being forced to also give away CAP_SYSLOG.
Suggested-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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dq_data_lock is currently used to protect all modifications of quota
accounting information, consistency of quota accounting on the inode,
and dquot pointers from inode. As a result contention on the lock can be
pretty heavy.
Reduce the contention on the lock by protecting quota accounting
information by a new dquot->dq_dqb_lock and consistency of quota
accounting with inode usage by inode->i_lock.
This change reduces time to create 500000 files on ext4 on ramdisk by 50
different processes in separate directories by 6% when user quota is
turned on. When those 50 processes belong to 50 different users, the
improvement is about 9%.
Signed-off-by: Jan Kara <jack@suse.cz>
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Provide helper __inode_get_bytes() which assumes i_lock is already
acquired. Quota code will need this to be able to use i_lock to protect
consistency of quota accounting information and inode usage.
Signed-off-by: Jan Kara <jack@suse.cz>
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inode_add_rsv_space() and inode_sub_rsv_space() had only one callsite.
Inline them there directly. inode_claim_rsv_space() and
inode_reclaim_rsv_space() had two callsites so inline them there as
well. This will simplify further locking changes.
Signed-off-by: Jan Kara <jack@suse.cz>
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Filesystems that are journalling quotas generally don't need tracking of
dirty dquots in a list since forcing a transaction commit flushes all
quotas anyway. Allow filesystem to say it doesn't want dquots to be
tracked as it reduces contention on the dq_list_lock.
Signed-off-by: Jan Kara <jack@suse.cz>
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Currently every dquot carries a wait_queue_head_t used only when we are
turning quotas off to wait for last users to drop dquot references.
Since such rare case is not performance sensitive in any means, just use
a global waitqueue for this and save space in struct dquot. Also convert
the logic to use wait_event() instead of open-coding it.
Signed-off-by: Jan Kara <jack@suse.cz>
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git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux into drm-next
omapdrm changes for v4.14
* HDMI hot plug IRQ support (instead of polling)
* Big driver cleanup from Laurent (no functional changes)
* OMAP5 DSI support (only the pinmuxing was missing)
* tag 'omapdrm-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux: (60 commits)
drm/omap: Potential NULL deref in omap_crtc_duplicate_state()
drm/omap: remove no-op cleanup code
drm/omap: rename omapdrm device back
drm: omapdrm: Remove omapdrm platform data
ARM: OMAP2+: Don't register omapdss device for omapdrm
ARM: OMAP2+: Remove unused omapdrm platform device
drm: omapdrm: Remove the omapdss driver
drm: omapdrm: Register omapdrm platform device in omapdss driver
drm: omapdrm: hdmi: Don't allocate PHY features dynamically
drm: omapdrm: hdmi: Configure the PHY from the HDMI core version
drm: omapdrm: hdmi: Configure the PLL from the HDMI core version
drm: omapdrm: hdmi: Pass HDMI core version as integer to HDMI audio
drm: omapdrm: hdmi: Replace OMAP SoC model check with HDMI xmit version
drm: omapdrm: hdmi: Rename functions and structures to use hdmi_ prefix
drm/omap: add OMAP5 DSIPHY lane-enable support
drm/omap: use regmap_update_bit() when muxing DSI pads
drm: omapdrm: Remove dss_features.h
drm: omapdrm: Move supported outputs feature to dss driver
drm: omapdrm: Move DSS_FCK feature to dss driver
drm: omapdrm: Move PCD, LINEWIDTH and DOWNSCALE features to dispc driver
...
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Update my email address since epoch.ncsc.mil no longer exists.
MAINTAINERS and CREDITS are already correct.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes
yet.
Signed-off-by: Jan Kara <jack@suse.cz>
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Christian Brauner reported that if you use the TIOCGPTPEER ioctl() to
get a slave pty file descriptor, the resulting file descriptor doesn't
look right in /proc/<pid>/fd/<fd>. In particular, he wanted to use
readlink() on /proc/self/fd/<fd> to get the pathname of the slave pty
(basically implementing "ptsname{_r}()").
The reason for that was that we had generated the wrong 'struct path'
when we create the pty in ptmx_open().
In particular, the dentry was correct, but the vfsmount pointed to the
mount of the ptmx node. That _can_ be correct - in case you use
"/dev/pts/ptmx" to open the master - but usually is not. The normal
case is to use /dev/ptmx, which then looks up the pts/ directory, and
then the vfsmount of the ptmx node is obviously the /dev directory, not
the /dev/pts/ directory.
We actually did have the right vfsmount available, but in the wrong
place (it gets looked up in 'devpts_acquire()' when we get a reference
to the pts filesystem), and so ptmx_open() used the wrong mnt pointer.
The end result of this confusion was that the pty worked fine, but when
if you did TIOCGPTPEER to get the slave side of the pty, end end result
would also work, but have that dodgy 'struct path'.
And then when doing "d_path()" on to get the pathname, the vfsmount
would not match the root of the pts directory, and d_path() would return
an empty pathname thinking that the entry had escaped a bind mount into
another mount.
This fixes the problem by making devpts_acquire() return the vfsmount
for the pts filesystem, allowing ptmx_open() to trivially just use the
right mount for the pts dentry, and create the proper 'struct path'.
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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'hotplug.2017.07.25b', 'misc.2017.08.17a', 'spin_unlock_wait_no.2017.08.17a', 'srcu.2017.07.27c' and 'torture.2017.07.24c' into HEAD
doc.2017.08.17a: Documentation updates.
fixes.2017.08.17a: RCU fixes.
hotplug.2017.07.25b: CPU-hotplug updates.
misc.2017.08.17a: Miscellaneous fixes outside of RCU (give or take conflicts).
spin_unlock_wait_no.2017.08.17a: Remove spin_unlock_wait().
srcu.2017.07.27c: SRCU updates.
torture.2017.07.24c: Torture-test updates.
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There is no agreed-upon definition of spin_unlock_wait()'s semantics,
and it appears that all callers could do just as well with a lock/unlock
pair. This commit therefore removes spin_unlock_wait() and related
definitions from core code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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There are cases where folks are using an interruptible swait when
using kthreads. This is rather confusing given you'd expect
interruptible waits to be -- interruptible, but kthreads are not
interruptible ! The reason for such practice though is to avoid
having these kthreads contribute to the system load average.
When systems are idle some kthreads may spend a lot of time blocking if
using swait_event_timeout(). This would contribute to the system load
average. On systems without preemption this would mean the load average
of an idle system is bumped to 2 instead of 0. On systems with PREEMPT=y
this would mean the load average of an idle system is bumped to 3
instead of 0.
This adds proper API using TASK_IDLE to make such goals explicit and
avoid confusion.
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Currently, the exit-time support for TASKS_RCU is open-coded in do_exit().
This commit creates exit_tasks_rcu_start() and exit_tasks_rcu_finish()
APIs for do_exit() use. This has the benefit of confining the use of the
tasks_rcu_exit_srcu variable to one file, allowing it to become static.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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The actual use of TASKS_RCU is only when PREEMPT, otherwise RCU-sched
is used instead. This commit therefore makes synchronize_rcu_tasks()
and call_rcu_tasks() available always, but mapped to synchronize_sched()
and call_rcu_sched(), respectively, when !PREEMPT. This approach also
allows some #ifdefs to be removed from rcutorture.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
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With the new lockdep crossrelease feature, which checks completions usage,
a false positive is reported in the workqueue code:
> Worker A : acquired of wfc.work -> wait for cpu_hotplug_lock to be released
> Task B : acquired of cpu_hotplug_lock -> wait for lock#3 to be released
> Task C : acquired of lock#3 -> wait for completion of barr->done
> (Task C is in lru_add_drain_all_cpuslocked())
> Worker D : wait for wfc.work to be released -> will complete barr->done
Such a dead lock can not happen because Task C's barr->done and Worker D's
barr->done can not be the same instance.
The reason of this false positive is we initialize all wq_barrier::done
at insert_wq_barrier() via init_completion(), which makes them belong to
the same lock class, therefore, impossible circles are reported.
To fix this, explicitly initialize the lockdep map for wq_barrier::done
in insert_wq_barrier(), so that the lock class key of wq_barrier::done
is a subkey of the corresponding work_struct, as a result we won't build
a dependency between a wq_barrier with a unrelated work, and we can
differ wq barriers based on the related works, so the false positive
above is avoided.
Also define the empty lockdep_init_map_crosslock() for !CROSSRELEASE
to make the code simple and away from unnecessary #ifdefs.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170817094622.12915-1-boqun.feng@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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'complete' is an adjective and LOCKDEP_COMPLETE sounds like 'lockdep is complete',
so pick a better name that uses a noun.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/1502960261-16206-3-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The existing map iteration helper for_each_efi_memory_desc_in_map can
only be used after the kernel initializes the EFI subsystem to set up
struct efi_memory_map.
Before that we also need iterate map descriptors which are stored in several
intermediate structures, like struct efi_boot_memmap for arch independent
usage and struct efi_info for x86 arch only.
Introduce efi_early_memdesc_ptr() to get pointer to a map descriptor, and
replace several places where that primitive is open coded.
Signed-off-by: Baoquan He <bhe@redhat.com>
[ Various improvements to the text. ]
Acked-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: ard.biesheuvel@linaro.org
Cc: fanc.fnst@cn.fujitsu.com
Cc: izumi.taku@jp.fujitsu.com
Cc: keescook@chromium.org
Cc: linux-efi@vger.kernel.org
Cc: n-horiguchi@ah.jp.nec.com
Cc: thgarnie@google.com
Link: http://lkml.kernel.org/r/20170816134651.GF21273@x1
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This implements refcount_t overflow protection on x86 without a noticeable
performance impact, though without the fuller checking of REFCOUNT_FULL.
This is done by duplicating the existing atomic_t refcount implementation
but with normally a single instruction added to detect if the refcount
has gone negative (e.g. wrapped past INT_MAX or below zero). When detected,
the handler saturates the refcount_t to INT_MIN / 2. With this overflow
protection, the erroneous reference release that would follow a wrap back
to zero is blocked from happening, avoiding the class of refcount-overflow
use-after-free vulnerabilities entirely.
Only the overflow case of refcounting can be perfectly protected, since
it can be detected and stopped before the reference is freed and left to
be abused by an attacker. There isn't a way to block early decrements,
and while REFCOUNT_FULL stops increment-from-zero cases (which would
be the state _after_ an early decrement and stops potential double-free
conditions), this fast implementation does not, since it would require
the more expensive cmpxchg loops. Since the overflow case is much more
common (e.g. missing a "put" during an error path), this protection
provides real-world protection. For example, the two public refcount
overflow use-after-free exploits published in 2016 would have been
rendered unexploitable:
http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/
http://cyseclabs.com/page?n=02012016
This implementation does, however, notice an unchecked decrement to zero
(i.e. caller used refcount_dec() instead of refcount_dec_and_test() and it
resulted in a zero). Decrements under zero are noticed (since they will
have resulted in a negative value), though this only indicates that a
use-after-free may have already happened. Such notifications are likely
avoidable by an attacker that has already exploited a use-after-free
vulnerability, but it's better to have them reported than allow such
conditions to remain universally silent.
On first overflow detection, the refcount value is reset to INT_MIN / 2
(which serves as a saturation value) and a report and stack trace are
produced. When operations detect only negative value results (such as
changing an already saturated value), saturation still happens but no
notification is performed (since the value was already saturated).
On the matter of races, since the entire range beyond INT_MAX but before
0 is negative, every operation at INT_MIN / 2 will trap, leaving no
overflow-only race condition.
As for performance, this implementation adds a single "js" instruction
to the regular execution flow of a copy of the standard atomic_t refcount
operations. (The non-"and_test" refcount_dec() function, which is uncommon
in regular refcount design patterns, has an additional "jz" instruction
to detect reaching exactly zero.) Since this is a forward jump, it is by
default the non-predicted path, which will be reinforced by dynamic branch
prediction. The result is this protection having virtually no measurable
change in performance over standard atomic_t operations. The error path,
located in .text.unlikely, saves the refcount location and then uses UD0
to fire a refcount exception handler, which resets the refcount, handles
reporting, and returns to regular execution. This keeps the changes to
.text size minimal, avoiding return jumps and open-coded calls to the
error reporting routine.
Example assembly comparison:
refcount_inc() before:
.text:
ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp)
refcount_inc() after:
.text:
ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp)
ffffffff8154614d: 0f 88 80 d5 17 00 js ffffffff816c36d3
...
.text.unlikely:
ffffffff816c36d3: 48 8d 4d f4 lea -0xc(%rbp),%rcx
ffffffff816c36d7: 0f ff (bad)
These are the cycle counts comparing a loop of refcount_inc() from 1
to INT_MAX and back down to 0 (via refcount_dec_and_test()), between
unprotected refcount_t (atomic_t), fully protected REFCOUNT_FULL
(refcount_t-full), and this overflow-protected refcount (refcount_t-fast):
2147483646 refcount_inc()s and 2147483647 refcount_dec_and_test()s:
cycles protections
atomic_t 82249267387 none
refcount_t-fast 82211446892 overflow, untested dec-to-zero
refcount_t-full 144814735193 overflow, untested dec-to-zero, inc-from-zero
This code is a modified version of the x86 PAX_REFCOUNT atomic_t
overflow defense from the last public patch of PaX/grsecurity, based
on my understanding of the code. Changes or omissions from the original
code are mine and don't reflect the original grsecurity/PaX code. Thanks
to PaX Team for various suggestions for improvement for repurposing this
code to be a refcount-only protection.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170815161924.GA133115@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Speculative processor accesses may reference any memory that has a
valid page table entry. While a speculative access won't generate
a machine check, it will log the error in a machine check bank. That
could cause escalation of a subsequent error since the overflow bit
will be then set in the machine check bank status register.
Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual
address of the page we want to map out otherwise we may trigger the
very problem we are trying to avoid. We use a non-canonical address
that passes through the usual Linux table walking code to get to the
same "pte".
Thanks to Dave Hansen for reviewing several iterations of this.
Also see:
http://marc.info/?l=linux-mm&m=149860136413338&w=2
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Elliott, Robert (Persistent Memory) <elliott@hpe.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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As found by syzkaller, malicious users can set whatever tx_queue_len
on a tun device and eventually crash the kernel.
Lets remove the ALIGN(XXX, SMP_CACHE_BYTES) thing since a small
ring buffer is not fast anyway.
Fixes: 2e0ab8ca83c1 ("ptr_ring: array based FIFO for pointers")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The only usage of vmbus_sendpacket_ctl was by vmbus_sendpacket.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The function vmbus_sendpacket_pagebuffer_ctl was never used directly.
Just have vmbus_send_pagebuffer
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This function is not used anywhere in current code.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Resolve issues with !CONFIG_BPF_SYSCALL and !STREAM_PARSER
net/core/filter.c: In function ‘do_sk_redirect_map’:
net/core/filter.c:1881:3: error: implicit declaration of function ‘__sock_map_lookup_elem’ [-Werror=implicit-function-declaration]
sk = __sock_map_lookup_elem(ri->map, ri->ifindex);
^
net/core/filter.c:1881:6: warning: assignment makes pointer from integer without a cast [enabled by default]
sk = __sock_map_lookup_elem(ri->map, ri->ifindex);
Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://anongit.freedesktop.org/git/drm-misc into drm-next
UAPI Changes:
- vc4: Allow userspace to dictate rendering order in submit_cl ioctl (Eric)
Cross-subsystem Changes:
- vboxvideo: One of Cihangir's patches applies to vboxvideo which is maintained
in staging
Core Changes:
- atomic_legacy_backoff is officially killed (Daniel)
- Extract drm_device.h (Daniel)
- Unregister drm device on unplug (Daniel)
- Rename deprecated drm_*_(un)?reference functions to drm_*_{get|put} (Cihangir)
Driver Changes:
- vc4: Error/destroy path cleanups, log level demotion, edid leak (Eric)
- various: Make various drm_*_funcs structs const (Bhumika)
- tinydrm: add support for LEGO MINDSTORMS EV3 LCD (David)
- various: Second half of .dumb_{map_offset|destroy} defaults set (Noralf)
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: Bhumika Goyal <bhumirks@gmail.com>
Cc: Cihangir Akturk <cakturk@gmail.com>
Cc: David Lechner <david@lechnology.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
* tag 'drm-misc-next-2017-08-16' of git://anongit.freedesktop.org/git/drm-misc: (50 commits)
drm/gem-cma-helper: Remove drm_gem_cma_dumb_map_offset()
drm/virtio: Use the drm_driver.dumb_destroy default
drm/bochs: Use the drm_driver.dumb_destroy default
drm/mgag200: Use the drm_driver.dumb_destroy default
drm/exynos: Use .dumb_map_offset and .dumb_destroy defaults
drm/msm: Use the drm_driver.dumb_destroy default
drm/ast: Use the drm_driver.dumb_destroy default
drm/qxl: Use the drm_driver.dumb_destroy default
drm/udl: Use the drm_driver.dumb_destroy default
drm/cirrus: Use the drm_driver.dumb_destroy default
drm/tegra: Use .dumb_map_offset and .dumb_destroy defaults
drm/gma500: Use .dumb_map_offset and .dumb_destroy defaults
drm/mxsfb: Use .dumb_map_offset and .dumb_destroy defaults
drm/meson: Use .dumb_map_offset and .dumb_destroy defaults
drm/kirin: Use .dumb_map_offset and .dumb_destroy defaults
drm/vc4: Continue the switch to drm_*_put() helpers
drm/vc4: Fix leak of HDMI EDID
dma-buf: fix reservation_object_wait_timeout_rcu to wait correctly v2
dma-buf: add reservation_object_copy_fences (v2)
drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/soc
Pull "soc changes for omaps for v4.14" from Tony Lindgren:
SoC updates for omaps for v4.14. Most of the chages are to add
support for new dra762 SoC. The other changes are are for legacy
DMA code removal, and MMC quirk and iodelay config for dra7.
* tag 'omap-for-v4.14/soc-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: OMAP: dra7: powerdomain data: Register SoC specific powerdomains
ARM: dra762: Enable SMP for dra762
ARM: dra7: hwmod: Register dra76x specific hwmod
ARM: dra762: Add support for device identification
ARM: OMAP2+: board-generic: add support for dra762 family
ARM: OMAP2+: Select PINCTRL_TI_IODELAY for SOC_DRA7XX
ARM: OMAP2+: Add pdata-quirks for MMC/SD on DRA74x EVM
ARM: OMAP2+: Remove unused legacy code for DMA
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http://git.linaro.org/people/jens.wiklander/linux-tee into next/drivers
Pull "Small fixes and enhancements for the TEE subsystem" from Jens Wiklander:
* tag 'tee-drv-for-4.14' of http://git.linaro.org/people/jens.wiklander/linux-tee:
tee: optee: sync with new naming of interrupts
tee: indicate privileged dev in gen_caps
tee: optee: interruptible RPC sleep
tee: optee: add const to tee_driver_ops and tee_desc structures
tee: tee_shm: Constify dma_buf_ops structures.
tee: add forward declaration for struct device
tee: optee: fix uninitialized symbol 'parg'
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Instead add a mechanism to ensure that the request doesn't disappear
from underneath us while copying from the socket. We do this by
preventing xprt_release() from freeing the XDR buffers until the
flag RPC_TASK_MSG_RECV has been cleared from the request.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
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Recently we added a new map type called dev map used to forward XDP
packets between ports (6093ec2dc313). This patches introduces a
similar notion for sockets.
A sockmap allows users to add participating sockets to a map. When
sockets are added to the map enough context is stored with the
map entry to use the entry with a new helper
bpf_sk_redirect_map(map, key, flags)
This helper (analogous to bpf_redirect_map in XDP) is given the map
and an entry in the map. When called from a sockmap program, discussed
below, the skb will be sent on the socket using skb_send_sock().
With the above we need a bpf program to call the helper from that will
then implement the send logic. The initial site implemented in this
series is the recv_sock hook. For this to work we implemented a map
attach command to add attributes to a map. In sockmap we add two
programs a parse program and a verdict program. The parse program
uses strparser to build messages and pass them to the verdict program.
The parse programs use the normal strparser semantics. The verdict
program is of type SK_SKB.
The verdict program returns a verdict SK_DROP, or SK_REDIRECT for
now. Additional actions may be added later. When SK_REDIRECT is
returned, expected when bpf program uses bpf_sk_redirect_map(), the
sockmap logic will consult per cpu variables set by the helper routine
and pull the sock entry out of the sock map. This pattern follows the
existing redirect logic in cls and xdp programs.
This gives the flow,
recv_sock -> str_parser (parse_prog) -> verdict_prog -> skb_send_sock
\
-> kfree_skb
As an example use case a message based load balancer may use specific
logic in the verdict program to select the sock to send on.
Sample programs are provided in future patches that hopefully illustrate
the user interfaces. Also selftests are in follow-on patches.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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