The goal is to integrate the SYSENTER and SYSCALL32 entry paths
with the INT80 path. SYSENTER clobbers ESP and EIP. SYSCALL32
clobbers ECX (and, invisibly, R11). SYSRETL (long mode to
compat mode) clobbers ECX and, invisibly, R11. SYSEXIT (which
we only need for native 32-bit) clobbers ECX and EDX.
This means that we'll need to provide ESP to the kernel in a
register (I chose ECX, since it's only needed for SYSENTER) and
we need to provide the args that normally live in ECX and EDX in
memory.
The epilogue needs to restore ECX and EDX, since user code
relies on regs being preserved.
We don't need to do anything special about EIP, since the kernel
already knows where we are. The kernel will eventually need to
know where int $0x80 lands, so add a vdso_image entry for it.
The only user-visible effect of this code is that ptrace-induced
changes to ECX and EDX during fast syscalls will be lost. This
is already the case for the SYSENTER path.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/b860925adbee2d2627a0671fbfe23a7fd04127f8.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull NFS client bugfixes from Trond Myklebust:
"Highlights include:
Bugfixes:
- Fix a use-after-free bug in the RPC/RDMA client
- Fix a write performance regression
- Fix up page writeback accounting
- Don't try to reclaim unused state owners
- Fix a NFSv4 nograce recovery hang
- reset states to use open_stateid when returning delegation
voluntarily
- Fix a tracepoint NULL-pointer dereference"
* tag 'nfs-for-4.3-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: Fix a tracepoint NULL-pointer dereference
nfs4: reset states to use open_stateid when returning delegation voluntarily
NFSv4: Fix a nograce recovery hang
NFSv4.1: nfs4_opendata_check_deleg needs to handle NFS4_OPEN_CLAIM_DELEG_CUR_FH
NFSv4: Don't try to reclaim unused state owners
NFS: Fix a write performance regression
NFS: Fix up page writeback accounting
xprtrdma: disconnect and flush cqs before freeing buffers
This reverts commit 998ef75ddb.
The commit itself does not appear to be buggy per se, but it is exposing
a bug in ext4 (and Ted thinks ext3 too, but we solved that by getting
rid of it). It's too late in the release cycle to really worry about
this, even if Dave Hansen has a patch that may actually fix the
underlying ext4 problem. We can (and should) revisit this for the next
release.
The problem is that moving the prefaulting later now exposes a special
case with partially successful writes that isn't handled correctly. And
the prefaulting likely isn't normally even that much of a performance
issue - it looks like at least one reason Dave saw this in his
performance tests is that he also ran them on Skylake that now supports
the new SMAP code, which makes the normally very cheap user space
prefaulting noticeably more expensive.
Bisected-and-acked-by: Ted Ts'o <tytso@mit.edu>
Analyzed-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Running xfstest generic/013 with the tracepoint nfs:nfs4_open_file
enabled produces a NULL-pointer dereference when calculating fileid and
filehandle of the opened file. Fix this by checking if state is NULL
before trying to use the inode pointer.
Reported-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull xen bug fixes from David Vrabel:
- Fix VM save performance regression with x86 PV guests
- Make kexec work in x86 PVHVM guests (if Xen has the soft-reset ABI)
- Other minor fixes.
* tag 'for-linus-4.3b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen/p2m: hint at the last populated P2M entry
x86/xen: Do not clip xen_e820_map to xen_e820_map_entries when sanitizing map
x86/xen: Support kexec/kdump in HVM guests by doing a soft reset
xen/x86: Don't try to write syscall-related MSRs for PV guests
xen: use correct type for HYPERVISOR_memory_op()
Pull s390 fixes from Martin Schwidefsky:
"Three bug fixes and an update to the default configuration"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/defconfig: set SCSI_DH=y
s390/vtime: correct scaled cputime of partially idle CPUs
s390/boot/decompression: disable floating point in decompressor
s390/numa: use correct type for node_to_cpumask_map
Pull CIFS fixes from Steve French:
"Two fixes for problems pointed out by automated tools.
Thanks PaX/grsecurity team and Dan Carpenter (and the Smatch tool)"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
[CIFS] Update cifs version number
[SMB3] Do not fall back to SMBWriteX in set_file_size error cases
[SMB3] Missing null tcon check
With commit 633d6f17cd (x86/xen: prepare
p2m list for memory hotplug) the P2M may be sized to accomdate a much
larger amount of memory than the domain currently has.
When saving a domain, the toolstack must scan all the P2M looking for
populated pages. This results in a performance regression due to the
unnecessary scanning.
Instead of reporting (via shared_info) the maximum possible size of
the P2M, hint at the last PFN which might be populated. This hint is
increased as new leaves are added to the P2M (in the expectation that
they will be used for populated entries).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: <stable@vger.kernel.org> # 4.0+
Pull strscpy string copy function implementation from Chris Metcalf.
Chris sent this during the merge window, but I waffled back and forth on
the pull request, which is why it's going in only now.
The new "strscpy()" function is definitely easier to use and more secure
than either strncpy() or strlcpy(), both of which are horrible nasty
interfaces that have serious and irredeemable problems.
strncpy() has a useless return value, and doesn't NUL-terminate an
overlong result. To make matters worse, it pads a short result with
zeroes, which is a performance disaster if you have big buffers.
strlcpy(), by contrast, is a mis-designed "fix" for strlcpy(), lacking
the insane NUL padding, but having a differently broken return value
which returns the original length of the source string. Which means
that it will read characters past the count from the source buffer, and
you have to trust the source to be properly terminated. It also makes
error handling fragile, since the test for overflow is unnecessarily
subtle.
strscpy() avoids both these problems, guaranteeing the NUL termination
(but not excessive padding) if the destination size wasn't zero, and
making the overflow condition very obvious by returning -E2BIG. It also
doesn't read past the size of the source, and can thus be used for
untrusted source data too.
So why did I waffle about this for so long?
Every time we introduce a new-and-improved interface, people start doing
these interminable series of trivial conversion patches.
And every time that happens, somebody does some silly mistake, and the
conversion patch to the improved interface actually makes things worse.
Because the patch is mindnumbing and trivial, nobody has the attention
span to look at it carefully, and it's usually done over large swatches
of source code which means that not every conversion gets tested.
So I'm pulling the strscpy() support because it *is* a better interface.
But I will refuse to pull mindless conversion patches. Use this in
places where it makes sense, but don't do trivial patches to fix things
that aren't actually known to be broken.
* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
tile: use global strscpy() rather than private copy
string: provide strscpy()
Make asm/word-at-a-time.h available on all architectures
Pull md fixes from Neil Brown:
"Assorted fixes for md in 4.3-rc.
Two tagged for -stable, and one is really a cleanup to match and
improve kmemcache interface.
* tag 'md/4.3-fixes' of git://neil.brown.name/md:
md/bitmap: don't pass -1 to bitmap_storage_alloc.
md/raid1: Avoid raid1 resync getting stuck
md: drop null test before destroy functions
md: clear CHANGE_PENDING in readonly array
md/raid0: apply base queue limits *before* disk_stack_limits
md/raid5: don't index beyond end of array in need_this_block().
raid5: update analysis state for failed stripe
md: wait for pending superblock updates before switching to read-only
Pull MIPS updates from Ralf Baechle:
"This week's round of MIPS fixes:
- Fix JZ4740 build
- Fix fallback to GFP_DMA
- FP seccomp in case of ENOSYS
- Fix bootmem panic
- A number of FP and CPS fixes
- Wire up new syscalls
- Make sure BPF assembler objects can properly be disassembled
- Fix BPF assembler code for MIPS I"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: scall: Always run the seccomp syscall filters
MIPS: Octeon: Fix kernel panic on startup from memory corruption
MIPS: Fix R2300 FP context switch handling
MIPS: Fix octeon FP context switch handling
MIPS: BPF: Fix load delay slots.
MIPS: BPF: Do all exports of symbols with FEXPORT().
MIPS: Fix the build on jz4740 after removing the custom gpio.h
MIPS: CPS: #ifdef on CONFIG_MIPS_MT_SMP rather than CONFIG_MIPS_MT
MIPS: CPS: Don't include MT code in non-MT kernels.
MIPS: CPS: Stop dangling delay slot from has_mt.
MIPS: dma-default: Fix 32-bit fall back to GFP_DMA
MIPS: Wire up userfaultfd and membarrier syscalls.
Pull irq fixes from Thomas Gleixner:
"This update contains:
- Fix for a long standing race affecting /proc/irq/NNN
- One line fix for ARM GICV3-ITS counting the wrong data
- Warning silencing in ARM GICV3-ITS. Another GCC trying to be
overly clever issue"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic-v3-its: Count additional LPIs for the aliased devices
irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined
genirq: Fix race in register_irq_proc()
The MIPS syscall handler code used to return -ENOSYS on invalid
syscalls. Whilst this is expected, it caused problems for seccomp
filters because the said filters never had the change to run since
the code returned -ENOSYS before triggering them. This caused
problems on the chromium testsuite for filters looking for invalid
syscalls. This has now changed and the seccomp filters are always
run even if the syscall is invalid. We return -ENOSYS once we
return from the seccomp filters. Moreover, similar codepaths have
been merged in the process which simplifies somewhat the overall
syscall code.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11236/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
