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Kirill A Shutemov reports that the kernel doesn't try to cap dest_count
in any way, and uses the number to allocate kernel memory. This causes
high order allocation warnings in the kernel log if someone passes in a
big enough value. We should clamp the allocation at PAGE_SIZE to avoid
stressing the VM.
The two existing users of the dedupe ioctl never send more than 120
requests, so we can safely clamp dest_range at PAGE_SIZE, because with
4k pages we can handle up to 127 dedupe candidates. Given the max
extent length of 16MB, we can end up doing 2GB of IO which is plenty.
[ Note: the "offsetof()" can't overflow, because 'count' is just a
16-bit integer. That's not obvious in the limited context of the
patch, so I'm noting it here because it made me go look. - Linus ]
Reported-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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All the VFS functions in the dedupe ioctl path return int status, so
the ioctl handler ought to as well.
Found by Coverity, CID 1350952.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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get_user_ex(x, ptr) should zero x on failure. It's not a lot of a leak
(at most we are leaking uninitialized 64bit value off the kernel stack,
and in a fairly constrained situation, at that), but the fix is trivial,
so...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ This sat in different branch from the uaccess fixes since mid-August ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When userspace sends KVM_SET_LAPIC, KVM schedules a check between
the vCPU's IRR and ISR and the IOAPIC redirection table, in order
to re-establish the IOAPIC's dest_map (the list of CPUs servicing
the real-time clock interrupt with the corresponding vectors).
However, __rtc_irq_eoi_tracking_restore_one was forgetting to
set dest_map->vectors. Because of this, the IOAPIC did not process
the real-time clock interrupt EOI, ioapic->rtc_status.pending_eoi
got stuck at a non-zero value, and further RTC interrupts were
reported to userspace as coalesced.
Fixes: 9e4aabe2bb3454c83dac8139cf9974503ee044db
Fixes: 4d99ba898dd0c521ca6cdfdde55c9b58aea3cb3d
Cc: stable@vger.kernel.org
Cc: Joerg Roedel <jroedel@suse.de>
Cc: David Gilbert <dgilbert@redhat.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Commit 88e957d6e47f ("xen: introduce xen_vcpu_id mapping") broke SMP
ARM guests on Xen. When FIFO-based event channels are in use (this is
the default), evtchn_fifo_alloc_control_block() is called on
CPU_UP_PREPARE event and this happens before we set up xen_vcpu_id
mapping in xen_starting_cpu. Temporary fix the issue by setting direct
Linux CPU id <-> Xen vCPU id mapping for all possible CPUs at boot. We
don't currently support kexec/kdump on Xen/ARM so these ids always
match.
In future, we have several ways to solve the issue, e.g.:
- Eliminate all hypercalls from CPU_UP_PREPARE, do them from the
starting CPU. This can probably be done for both x86 and ARM and, if
done, will allow us to get Xen's idea of vCPU id from CPUID/MPIDR on
the starting CPU directly, no messing with ACPI/device tree
required.
- Save vCPU id information from ACPI/device tree on ARM and use it to
initialize xen_vcpu_id mapping. This is the same trick we currently
do on x86.
Reported-by: Julien Grall <julien.grall@arm.com>
Tested-by: Wei Chen <Wei.Chen@arm.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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really ugly, but apparently avr32 compilers turns access_ok() into
something so bad that they want it in assembler. Left that way,
zeroing added in inline wrapper.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It could be done in exception-handling bits in __get_user_b() et.al.,
but the surgery involved would take more knowledge of sh64 details
than I have or _want_ to have.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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* should zero on any failure
* __get_user() should use __copy_from_user(), not copy_from_user()
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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should clear on access_ok() failures. Also remove the useless
range truncation logics.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... that should zero on faults. Also remove the <censored> helpful
logics wrt range truncation copied from ppc32. Where it had ever
been needed only in case of copy_from_user() *and* had not been merged
into the mainline until a month after the need had disappeared.
A decade before openrisc went into mainline, I might add...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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a) should not leave crap on fault
b) should _not_ require access_ok() in any cases.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.
Verified using following
| {
| u32 bogus1 = 0xdeadbeef;
| u64 bogus2 = 0xdead;
| int rc1, rc2;
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| pr_info("Orig values %x %llx\n", bogus1, bogus2);
| rc1 = get_user(bogus1, (u32 __user *)0x40000000);
| rc2 = get_user(bogus2, (u64 __user *)0x50000000);
| pr_info("access %d %d, new values %x %llx\n",
| rc1, rc2, bogus1, bogus2);
| }
| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It's -EFAULT, not -1 (and contrary to the comment in there,
__strnlen_user() can return 0 - on faults).
Cc: stable@vger.kernel.org
Acked-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It should check access_ok(). Otherwise a bunch of places turn into
trivially exploitable rootholes.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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* copy_from_user() on access_ok() failure ought to zero the destination
* none of those primitives should skip the access_ok() check in case of
small constant size.
Cc: stable@vger.kernel.org
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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both for access_ok() failures and for faults halfway through
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Starting with v4.8, we allow a PCIe port to runtime suspend to D3hot if the
port itself and its children satisfy a number of conditions. Once a child
is removed, we recheck those conditions in case the removed device was
blocking the port from suspending.
The rechecking needs to happen *after* the device has been removed from the
bus it resides on. Otherwise when walking the port's subordinate bus in
pci_bridge_d3_update(), the device being removed would erroneously still be
taken into account.
However the device is removed from the bus_list in pci_destroy_dev() and we
currently recheck *before* that. Fix it.
Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <mika.westerberg@linux.intel.com>
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A recent change removed the dependency on BLK_DEV_NVME, which implies
the dependency on PCI and BLOCK. We don't need CONFIG_PCI, but without
CONFIG_BLOCK we get tons of build errors, e.g.
In file included from drivers/nvme/host/core.c:16:0:
linux/blk-mq.h:182:33: error: 'struct gendisk' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
drivers/nvme/host/core.c: In function 'nvme_setup_rw':
drivers/nvme/host/core.c:295:21: error: implicit declaration of function 'rq_data_dir' [-Werror=implicit-function-declaration]
drivers/nvme/host/nvme.h: In function 'nvme_map_len':
drivers/nvme/host/nvme.h:217:6: error: implicit declaration of function 'req_op' [-Werror=implicit-function-declaration]
drivers/nvme/host/scsi.c: In function 'nvme_trans_bdev_limits_page':
drivers/nvme/host/scsi.c:768:85: error: implicit declaration of function 'queue_max_hw_sectors' [-Werror=implicit-function-declaration]
This adds back the specific CONFIG_BLOCK dependency to avoid broken
configurations.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: aa71987472a9 ("nvme: fabrics drivers don't need the nvme-pci driver")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
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If there is an error on req->mr, req->mr is set to null, however
the following statement sets req->mr->need_inval causing a null
pointer dereference. Fix this by bailing out to label 'out' to
immediately return and hence skip over the offending null pointer
dereference.
Fixes: f5b7b559e1488 ("nvme-rdma: Get rid of duplicate variable")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
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Change nvme-rdma to use the IB Client API to detect device removal.
This has the wonderful benefit of being able to blow away all the
ib/rdma_cm resources for the device being removed. No craziness about
not destroying the cm_id handling the event. No deadlocks due to broken
iw_cm/rdma_cm/iwarp dependencies. And no need to have a bound cm_id
around during controller recovery/reconnect to catch device removal
events.
We don't use the device_add aspect of the ib_client service since we only
want to create resources for an IB device if we have a target utilizing
that device.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
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When we get a surprise disconnect from the target we queue a periodic
reconnect (which is the sane thing to do...).
We only move the queues out of CONNECTED when we retry to reconnect (after
10 seconds in the default case) but we stop the blk queues immediately
so we are not bothered with traffic from now on. If delete() is kicking
off in this period the queues are still in CONNECTED state.
Part of the delete sequence is trying to issue ctrl shutdown if the
admin queue is CONNECTED (which it is!). This request is issued but
stuck in blk-mq waiting for the queues to start again. This might be
the one preventing us from forward progress...
The patch separates the queue flags to CONNECTED and DELETING. Now we
will move out of CONNECTED as soon as error recovery kicks in (before
stopping the queues) and DELETING is on when we start the queue deletion.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
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When port is down, tx drop counter update is not needed.
Updating the counter in this case can cause a kernel
panic as when the port is down, ring can be NULL.
Fixes: 63a664b7e92b ("net/mlx4_en: fix tx_dropped bug")
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds a capability check before enabling DCBX.
In addition, it re-organizes the relevant data structures,
and fixes a typo in a define.
Fixes: af7d51852631 ("net/mlx4_en: Add DCB PFC support through CEE netlink commands")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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mlx4_en_dcbnl_set_state() returns u8, the return value from
mlx4_en_setup_tc() could be negative in case of failure, so fix that.
Fixes: af7d51852631 ("net/mlx4_en: Add DCB PFC support through CEE netlink commands")
Signed-off-by: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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mlx4_en_dcbnl_set_all() returns u8, so return value can't be negative in
case of failure.
Fixes: af7d51852631 ("net/mlx4_en: Add DCB PFC support through CEE netlink commands")
Signed-off-by: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Rana Shahout <ranas@mellanox.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit aa71987472a9 ("nvme: fabrics drivers don't need the nvme-pci
driver") removed the dependency on BLK_DEV_NVME, but the cdoe does
depend on the block layer (which used to be an implicit dependency
through BLK_DEV_NVME).
Otherwise you get various errors from the kbuild test robot random
config testing when that happens to hit a configuration with BLOCK
device support disabled.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jay Freyensee <james_p_freyensee@linux.intel.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ensure that we conform to the algorithm described in RFC5661, section
18.36.4 for when to bump the sequence id. In essence we do it for all
cases except when the RPC call timed out, or in case of the server returning
NFS4ERR_DELAY or NFS4ERR_STALE_CLIENTID.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
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Due to a mistake in the hardware manual, the FWSLC and POST1-4 registers
were not documented and left out of the driver for RZ/A making the CAM
feature non-operational.
Additionally, when the offset values for POST1-4 are left blank, the driver
attempts to set them using an offset of 0xFFFF which can cause a memory
corruption or panic.
This patch fixes the panic and properly enables CAM.
Reported-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexander hit the WARN_ON_ONCE(!event) on his Skylake while running
the perf fuzzer.
This means the PEBSv3 record included a status bit for an inactive
event, something that _should_ not happen.
Move the code that filters the status bits against our known PEBS
events up a spot to guarantee we only deal with events we know about.
Further add "continue" statements to the WARN_ON_ONCE()s such that
we'll not die nor generate silly events in case we ever do hit them
again.
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.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 <vince@deater.net>
Cc: stable@vger.kernel.org
Fixes: a3d86542de88 ("perf/x86/intel/pebs: Add PEBSv3 decoding")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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At the moment, intel_bts will WARN() out if there is more than one
event writing to the same ring buffer, via SET_OUTPUT, and will only
send data from one event to a buffer.
There is no reason to have this warning in, so kill it.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
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@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-6-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Since BTS doesn't have a dedicated PMI status bit, the driver needs to
take extra care to check for the condition that triggers it to avoid
spurious NMI warnings.
Regardless of the local BTS context state, the only way of knowing that
the NMI is ours is to compare the write pointer against the interrupt
threshold.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
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@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-5-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The intel_bts driver is using a CPU-local 'started' variable to order
callbacks and PMIs and make sure that AUX transactions don't get messed
up. However, the ordering rules in regard to this variable is a complete
mess, which recently resulted in perf_fuzzer-triggered warnings and
panics.
The general ordering rule that is patch is enforcing is that this
cpu-local variable be set only when the cpu-local AUX transaction is
active; consequently, this variable is to be checked before the AUX
related bits can be touched.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
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@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-4-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The order of accesses to ring buffer's aux_mmap_count and aux_refcount
has to be preserved across the users, namely perf_mmap_close() and
perf_aux_output_begin(), otherwise the inversion can result in the latter
holding the last reference to the aux buffer and subsequently free'ing
it in atomic context, triggering a warning.
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 257 at kernel/events/ring_buffer.c:541 __rb_free_aux+0x11a/0x130
> CPU: 0 PID: 257 Comm: stopbug Not tainted 4.8.0-rc1+ #2596
> Call Trace:
> [<ffffffff810f3e0b>] __warn+0xcb/0xf0
> [<ffffffff810f3f3d>] warn_slowpath_null+0x1d/0x20
> [<ffffffff8121182a>] __rb_free_aux+0x11a/0x130
> [<ffffffff812127a8>] rb_free_aux+0x18/0x20
> [<ffffffff81212913>] perf_aux_output_begin+0x163/0x1e0
> [<ffffffff8100c33a>] bts_event_start+0x3a/0xd0
> [<ffffffff8100c42d>] bts_event_add+0x5d/0x80
> [<ffffffff81203646>] event_sched_in.isra.104+0xf6/0x2f0
> [<ffffffff8120652e>] group_sched_in+0x6e/0x190
> [<ffffffff8120694e>] ctx_sched_in+0x2fe/0x5f0
> [<ffffffff81206ca0>] perf_event_sched_in+0x60/0x80
> [<ffffffff81206d1b>] ctx_resched+0x5b/0x90
> [<ffffffff81207281>] __perf_event_enable+0x1e1/0x240
> [<ffffffff81200639>] event_function+0xa9/0x180
> [<ffffffff81202000>] ? perf_cgroup_attach+0x70/0x70
> [<ffffffff8120203f>] remote_function+0x3f/0x50
> [<ffffffff811971f3>] flush_smp_call_function_queue+0x83/0x150
> [<ffffffff81197bd3>] generic_smp_call_function_single_interrupt+0x13/0x60
> [<ffffffff810a6477>] smp_call_function_single_interrupt+0x27/0x40
> [<ffffffff81a26ea9>] call_function_single_interrupt+0x89/0x90
> [<ffffffff81120056>] finish_task_switch+0xa6/0x210
> [<ffffffff81120017>] ? finish_task_switch+0x67/0x210
> [<ffffffff81a1e83d>] __schedule+0x3dd/0xb50
> [<ffffffff81a1efe5>] schedule+0x35/0x80
> [<ffffffff81128031>] sys_sched_yield+0x61/0x70
> [<ffffffff81a25be5>] entry_SYSCALL_64_fastpath+0x18/0xa8
> ---[ end trace 6235f556f5ea83a9 ]---
This patch puts the checks in perf_aux_output_begin() in the same order
as that of perf_mmap_close().
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
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@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-3-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In the mmap_close() path we need to stop all the AUX events that are
writing data to the AUX area that we are unmapping, before we can
safely free the pages. To determine if an event needs to be stopped,
we're comparing its ->rb against the one that's getting unmapped.
However, a SET_OUTPUT ioctl may turn up inside an AUX transaction
and swizzle event::rb to some other ring buffer, but the transaction
will keep writing data to the old ring buffer until the event gets
scheduled out. At this point, mmap_close() will skip over such an
event and will proceed to free the AUX area, while it's still being
used by this event, which will set off a warning in the mmap_close()
path and cause a memory corruption.
To avoid this, always stop an AUX event before its ->rb is updated;
this will release the (potentially) last reference on the AUX area
of the buffer. If the event gets restarted, its new ring buffer will
be used. If another SET_OUTPUT comes and switches it back to the
old ring buffer that's getting unmapped, it's also fine: this
ring buffer's aux_mmap_count will be zero and AUX transactions won't
start any more.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
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@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-2-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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