This patch adds variants of rcu_dereference() that handle
situations where the RCU-protected data structure cannot change,
perhaps due to our holding the update-side lock, or where the
RCU-protected pointer is only to be fetched, not dereferenced.
These are needed due to some performance concerns with using
rcu_dereference() where it is not required, aside from the need
for lockdep/sparse checking.
The new rcu_access_pointer() primitive is for the case where the
pointer is be fetch and not dereferenced. This primitive may be
used without protection, RCU or otherwise, due to the fact that
it uses ACCESS_ONCE().
The new rcu_dereference_protected() primitive is for the case
where updates are prevented, for example, due to holding the
update-side lock. This primitive does neither ACCESS_ONCE() nor
smp_read_barrier_depends(), so can only be used when updates are
somehow prevented.
Suggested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <1270852752-25278-1-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When crash happens in interrupt context there is no userspace context.
We always use current->active_mm in those cases.
Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
From: Imre Deak <imre.deak@nokia.com>
Signal handlers can use floating point, so prevent them to corrupt
the main thread's VFP context. So far there were two signal stack
frame formats defined based on the VFP implementation, but the user
struct used for ptrace covers all posibilities, so use it for the
signal stack too.
Introduce also a new user struct for VFP exception registers. In
this too fields not relevant to the current VFP architecture are
ignored.
Support to save / restore the exception registers was added by
Will Deacon.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
From: Imre Deak <imre.deak@nokia.com>
Recently the UP versions of these functions were refactored and as
a side effect it became possible to call them for the current thread.
This isn't true for the SMP versions however, so fix this up.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The VIVT cache of a highmem page is always flushed before the page
is unmapped. This cache flush is explicit through flush_cache_kmaps()
in flush_all_zero_pkmaps(), or through __cpuc_flush_dcache_area() in
kunmap_atomic(). There is also an implicit flush of those highmem pages
that were part of a process that just terminated making those pages free
as the whole VIVT cache has to be flushed on every task switch. Hence
unmapped highmem pages need no cache maintenance in that case.
However unmapped pages may still be cached with a VIPT cache because the
cache is tagged with physical addresses. There is no need for a whole
cache flush during task switching for that reason, and despite the
explicit cache flushes in flush_all_zero_pkmaps() and kunmap_atomic(),
some highmem pages that were mapped in user space end up still cached
even when they become unmapped.
So, we do have to perform cache maintenance on those unmapped highmem
pages in the context of DMA when using a VIPT cache. Unfortunately,
it is not possible to perform that cache maintenance using physical
addresses as all the L1 cache maintenance coprocessor functions accept
virtual addresses only. Therefore we have no choice but to set up a
temporary virtual mapping for that purpose.
And of course the explicit cache flushing when unmapping a highmem page
on a system with a VIPT cache now can go, which should increase
performance.
While at it, because the code in __flush_dcache_page() has to be modified
anyway, let's also make sure the mapped highmem pages are pinned with
kmap_high_get() for the duration of the cache maintenance operation.
Because kunmap() does unmap highmem pages lazily, it was reported by
Gary King <GKing@nvidia.com> that those pages ended up being unmapped
during cache maintenance on SMP causing segmentation faults.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
From: Julien Langer <julien.langer@gmail.com>
AT91: when turning off the PLLs during suspend, don't wait for the lock
flag to be set. Previously the code would always run into the loop
limitation of 1000 iterations because the flag is never set when turning
the PLLs off.
Comments from Anders Larsen:
(in http://marc.info/?l=linux-kernel&m=127058929724193&w=2)
Signed-off-by: Julien Langer <julien.langer@gmail.com>
Signed-off-by: Anders Larsen <al@alarsen.net>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This is a fix for bug 572201 @ bugs.debian.org
This patch fixes the TX_LIMIT feature flag. The previous logic check
for TX_LIMIT2 also took into account a device that only had TX_LIMIT
set.
Reported-by: Stephen Mulcahu <stephen.mulcahy@deri.org>
Reported-by: Ben Huchings <ben@decadent.org.uk>
Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFSv4: fix delegated locking
NFS: Ensure that the WRITE and COMMIT RPC calls are always uninterruptible
NFS: Fix a race with the new commit code
NFS: Ensure that writeback_single_inode() calls write_inode() when syncing
NFS: Fix the mode calculation in nfs_find_open_context
NFSv4: Fall back to ordinary lookup if nfs4_atomic_open() returns EISDIR
Use a separate class for ceph sockets to prevent lockdep confusion.
Because ceph sockets only get passed kernel pointers, there is no
dependency from sk_lock -> mmap_sem. If we share the same class as other
sockets, lockdep detects a circular dependency from
mmap_sem (page fault) -> fs mutex -> sk_lock -> mmap_sem
because dependencies are noted from both ceph and user contexts. Using
a separate class prevents the sk_lock(ceph) -> mmap_sem dependency and
makes lockdep happy.
Signed-off-by: Sage Weil <sage@newdream.net>
We were missing space for the directory cap. The result was a BUG at
fs/ceph/caps.c:2178.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
This simplifies the calling convention, and fixes a bug where we queue a
capsnap with a context other than i_head_snapc (the one that matches the
dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback
completion when a capsnap matching the writeback snapc could not be found.
Signed-off-by: Sage Weil <sage@newdream.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
sparc64: Add some more commentary to __raw_local_irq_save()
sparc64: Fix memory leak in pci_register_iommu_region().
sparc64: Add kmemleak annotation to sun4v_build_virq()
sparc64: Support kmemleak.
sparc64: Add function graph tracer support.
sparc64: Give a stack frame to the ftrace call sites.
sparc64: Use a seperate counter for timer interrupts and NMI checks, like x86.
sparc64: Remove profiling from some low-level bits.
sparc64: Kill unnecessary static on local var in ftrace_call_replace().
sparc64: Kill CONFIG_STACK_DEBUG code.
sparc64: Add HAVE_FUNCTION_TRACE_MCOUNT_TEST and tidy up.
sparc64: Adjust __raw_local_irq_save() to cooperate in NMIs.
sparc64: Use kstack_valid() in die_if_kernel().
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (25 commits)
smc91c92_cs: define multicast_table as unsigned char
can: avoids a false warning
e1000e: stop cleaning when we reach tx_ring->next_to_use
igb: restrict WoL for 82576 ET2 Quad Port Server Adapter
virtio_net: missing sg_init_table
Revert "tcp: Set CHECKSUM_UNNECESSARY in tcp_init_nondata_skb"
iwlwifi: need check for valid qos packet before free
tcp: Set CHECKSUM_UNNECESSARY in tcp_init_nondata_skb
udp: fix for unicast RX path optimization
myri10ge: fix rx_pause in myri10ge_set_pauseparam
net: corrected documentation for hardware time stamping
stmmac: use resource_size()
x.25 attempts to negotiate invalid throughput
x25: Patch to fix bug 15678 - x25 accesses fields beyond end of packet.
bridge: Fix IGMP3 report parsing
cnic: Fix crash during bnx2x MTU change.
qlcnic: fix set mac addr
r6040: fix r6040_multicast_list
vhost-net: fix vq_memory_access_ok error checking
ath9k: fix double calls to ath_radio_enable
...
smc91c92_cs:
* define multicast_table as unsigned char
* remove unnecessary "#ifndef final_version"
Signed-off-by: Ken Kawasaki <ken_kawasaki@spring.nifty.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
At this point optlen == sizeof(sfilter) but some compilers are dumb.
Reported-by: Németh Márton <nm127@freemail.h
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tx ring buffers after tx_ring->next_to_use are volatile and could
change, possibly causing a crash. Stop cleaning when we hit
tx_ring->next_to_use.
Signed-off-by: Terry Loftin <terry.loftin@hp.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Restrict Wake-on-LAN to first port on 82576 ET2 quad port NICs, as it is
only supported there.
Signed-off-by: Stefan Assmann <sassmann@redhat.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The commit 29a4f2d3 used writel() at offset 0x26 which is
half-word aligned causing unaligned exceptions on a
Cortex-A8. The original patch solved the "aaci-pl041 fpga:04:
ac97 read back fail" issue on a soft reset. Reading from any
arbitrary aaci register seems to solve this issue.
Signed-off-by: Philby John <pjohn@mvista.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Found by kmemleak.
If request_resource() fails, we leak the struct resource we
allocated to represent the IOMMU mapping area.
This actually happens on sun4v machines because the IOMEM area is only
reported sans the IOMMU region, unlike all previous systems. I'll
need to fix that at some point, but for now fix the leak.
Signed-off-by: David S. Miller <davem@davemloft.net>
The only reference we store to this memory is in the form of a
physical address, so kmemleak can't see it.
Add a kmemleak_not_leak() annotation.
It's probably useful to be able to look at a dump of these things
either via debugfs or similar, and thus we could at some point store
them in some kind of table and therefore get rid of this annotation.
Signed-off-by: David S. Miller <davem@davemloft.net>
It's the only way we'll be able to implement the function
graph tracer properly.
A positive is that we no longer have to worry about the
linker over-optimizing the tail call, since we don't
use a tail call any more.
Signed-off-by: David S. Miller <davem@davemloft.net>
This keeps us from having to use kstat_irqs_cpu() from the NMI handler,
the former of which is a profiled function.
Instead we use a currently empty slot in the cpu_data
Signed-off-by: David S. Miller <davem@davemloft.net>
These include the timer implementation, perf events support, and the
performance counter register (pcr) programming layer.
Signed-off-by: David S. Miller <davem@davemloft.net>
Check function_trace_stop at ftrace_caller
Toss mcount_call and dummy call of ftrace_stub, unnecessary.
Document problems we'll have if the final kernel image link
ever turns on relaxation.
Properly size 'ftrace_call' so it looks right when inspecting
instructions under gdb et al.
Signed-off-by: David S. Miller <davem@davemloft.net>
If we are in an NMI then doing a plain raw_local_irq_disable() will
write PIL_NORMAL_MAX into %pil, which is lower than PIL_NMI, and thus
we'll re-enable NMIs and recurse.
Doing a simple:
%pil = %pil | PIL_NORMAL_MAX
does what we want, if we're already at PIL_NMI (15) we leave it at
that setting, else we set it to PIL_NORMAL_MAX (14).
This should get the function tracer working on sparc64.
Signed-off-by: David S. Miller <davem@davemloft.net>
This gets rid of a local function (is_kernel_stack()) which tries to
do the same thing, yet poorly in that it doesn't handle IRQ stacks
properly.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing sg_init_table for sg_set_buf in virtio_net which
induced in defer skb patch.
Reported-by: Thomas Müller <thomas@mathtm.de>
Tested-by: Thomas Müller <thomas@mathtm.de>
Signed-off-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* anonvma:
anonvma: when setting up page->mapping, we need to pick the _oldest_ anonvma
anon_vma: clone the anon_vma chain in the right order
vma_adjust: fix the copying of anon_vma chains
Simplify and comment on anon_vma re-use for anon_vma_prepare()
* master.kernel.org:/home/rmk/linux-2.6-arm: (21 commits)
ARM: Fix ioremap_cached()/ioremap_wc() for SMP platforms
ARM: 6043/1: AT91 slow-clock resume: Don't wait for a disabled PLL to lock
ARM: 6031/1: fix Thumb-2 decompressor
ARM: 6029/1: ep93xx: gpio.c: local functions should be static
ARM: 6028/1: ARM: add MAINTAINERS for U300
ARM: 6024/1: bcmring: fix missing down on semaphore in dma.c
MXC: mach_armadillo5x0: Add USB Host support.
ARM mach-mx3: duplicated include
ARM mach-mx3: duplicated include
imx31: add watchdog device on litekit board.
imx3: Add watchdog platform device support
MXC: mach-mx31_3ds: add support for freescale mc13783 power management device.
MXC: mach-mx31_3ds: Add SPI1 device support.
MXC: mach-mx31_3ds: Add support for on board NAND Flash.
MXC: mach-mx31_3ds: Update variable names over recent mach name modification.
imx31: fix parent clock for rtc
i.MX51: remove NFC AXI static mapping
i.MX51: determine silicon revision dynamically
i.MX51: map TZIC dynamically
i.MX51: Use correct clock for gpt
...
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: make sure the chunk allocator doesn't create zero length chunks
Btrfs: fix data enospc check overflow
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6:
quota: Fix possible dq_flags corruption
quota: Hide warnings about writes to the filesystem before quota was turned on
ext3: symlink must be handled via filesystem specific operation
ext2: symlink must be handled via filesystem specific operation
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (36 commits)
MIPS: Calculate proper ebase value for 64-bit kernels
MIPS: Alchemy: DB1200: Remove custom wait implementation
MIPS: Big Sur: Make defconfig more useful.
MIPS: Fix __vmalloc() etc. on MIPS for non-GPL modules
MIPS: Sibyte: Fix M3 TLB exception handler workaround.
MIPS: BCM63xx: Fix build failure in board_bcm963xx.c
MIPS: uasm: Add OR instruction.
MIPS: Sibyte: Apply M3 workaround only on affected chip types and versions.
MIPS: BCM63xx: Initialize gpio_out_low & out_high to current value at boot.
MIPS: BCM63xx: Register SSB SPROM fallback in board's first stage callback
MIPS: BCM63xx: Fix typo in cpu-feature-overrides file.
MIPS: BCM63xx: Add support for second uart.
MIPS: BCM63xx: Fix double gpio registration.
MIPS: BCM63xx: Add DWVS0 board
MIPS: BCM63xx: Add the RTA1025W-16 BCM6348-based board to suppported boards.
MIPS: BCM63xx: Fix BCM6338 and BCM6345 gpio count
MIPS: libgcc.h: Checkpatch cleanup
MIPS: Loongson-2F: Flush the branch target history in BTB and RAS
MIPS: Move signal trampolines off of the stack.
MIPS: Preliminary VDSO
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
nilfs2: fix typo "numer" -> "number" in alloc.c
nilfs2: Remove an uninitialization warning in nilfs_btree_propagate_v()
nilfs2: fix a wrong type conversion in nilfs_ioctl()
Otherwise we might be mapping in a page in a new mapping, but that page
(through the swapcache) would later be mapped into an old mapping too.
The page->mapping must be the case that works for everybody, not just
the mapping that happened to page it in first.
Here's the scenario:
- page gets allocated/mapped by process A. Let's call the anon_vma we
associate the page with 'A' to keep it easy to track.
- Process A forks, creating process B. The anon_vma in B is 'B', and has
a chain that looks like 'B' -> 'A'. Everything is fine.
- Swapping happens. The page (with mapping pointing to 'A') gets swapped
out (perhaps not to disk - it's enough to assume that it's just not
mapped any more, and lives entirely in the swap-cache)
- Process B pages it in, which goes like this:
do_swap_page ->
page = lookup_swap_cache(entry);
...
set_pte_at(mm, address, page_table, pte);
page_add_anon_rmap(page, vma, address);
And think about what happens here!
In particular, what happens is that this will now be the "first"
mapping of that page, so page_add_anon_rmap() used to do
if (first)
__page_set_anon_rmap(page, vma, address);
and notice what anon_vma it will use? It will use the anon_vma for
process B!
What happens then? Trivial: process 'A' also pages it in (nothing
happens, it's not the first mapping), and then process 'B' execve's
or exits or unmaps, making anon_vma B go away.
End result: process A has a page that points to anon_vma B, but
anon_vma B does not exist any more. This can go on forever. Forget
about RCU grace periods, forget about locking, forget anything like
that. The bug is simply that page->mapping points to an anon_vma
that was correct at one point, but was _not_ the one that was shared
by all users of that possible mapping.
Changing it to always use the deepest anon_vma in the anonvma chain gets
us to the safest model.
This can be improved in certain cases: if we know the page is private to
just this particular mapping (for example, it's a new page, or it is the
only swapcache entry), we could pick the top (most specific) anon_vma.
But that's a future optimization. Make it _work_ reliably first.
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Borislav Petkov <bp@alien8.de> [ "What do you know, I think you fixed it!" ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want to walk the chain in reverse order when cloning it, so that the
order of the result chain will be the same as the order in the source
chain. When we add entries to the chain, they go at the head of the
chain, so we want to add the source head last.
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Borislav Petkov <bp@alien8.de> [ "No, it still oopses" ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we move the boundaries between two vma's due to things like
mprotect, we need to make sure that the anon_vma of the pages that got
moved from one vma to another gets properly copied around. And that was
not always the case, in this rather hard-to-follow code sequence.
Clarify the code, and fix it so that it copies the anon_vma from the
right source.
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Borislav Petkov <bp@alien8.de> [ "Yeah, not so much this one either" ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This changes the anon_vma reuse case to require that we only reuse
simple anon_vma's - ie the case when the vma only has a single anon_vma
associated with it.
This means that a reuse of an anon_vma from an adjacent vma will always
guarantee that both vma's are associated not only with the same
anon_vma, they will also have the same anon_vma chain (of just a single
entry in this case).
And since anon_vma re-use was the only case where the same anon_vma
might be associated with different chains of anon_vma's, we now have the
case that every vma that shares the same anon_vma will always also have
the same chain. That makes it much easier to think about merging vma's
that share the same anon_vma's: you can always just drop the other
anon_vma chain in anon_vma_merge() since you know that they are always
identical.
This also splits up the function to validate the anon_vma re-use, and
adds a lot of commentary about the possible races.
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Borislav Petkov <bp@alien8.de> [ "That didn't fix it" ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When filldir returned an error (e.g. buffer full for a large directory),
we would leak a dentry reference, causing an oops on umount.
Signed-off-by: Sage Weil <sage@newdream.net>
