Commit Graph

10 Commits

Author SHA1 Message Date
Al Viro a08971e948 futex: arch_futex_atomic_op_inuser() calling conventions change
Move access_ok() in and pagefault_enable()/pagefault_disable() out.
Mechanical conversion only - some instances don't really need
a separate access_ok() at all (e.g. the ones only using
get_user()/put_user(), or architectures where access_ok()
is always true); we'll deal with that in followups.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-03-27 23:58:51 -04:00
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Jiri Slaby 30d6e0a419 futex: Remove duplicated code and fix undefined behaviour
There is code duplicated over all architecture's headers for
futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
and comparison of the result.

Remove this duplication and leave up to the arches only the needed
assembly which is now in arch_futex_atomic_op_inuser.

This effectively distributes the Will Deacon's arm64 fix for undefined
behaviour reported by UBSAN to all architectures. The fix was done in
commit 5f16a046f8 (arm64: futex: Fix undefined behaviour with
FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.

And as suggested by Thomas, check for negative oparg too, because it was
also reported to cause undefined behaviour report.

Note that s390 removed access_ok check in d12a29703 ("s390/uaccess:
remove pointless access_ok() checks") as access_ok there returns true.
We introduce it back to the helper for the sake of simplicity (it gets
optimized away anyway).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> [s390]
Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
Reviewed-by: Will Deacon <will.deacon@arm.com> [core/arm64]
Cc: linux-mips@linux-mips.org
Cc: Rich Felker <dalias@libc.org>
Cc: linux-ia64@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: peterz@infradead.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: sparclinux@vger.kernel.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: linux-s390@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-hexagon@vger.kernel.org
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-snps-arc@lists.infradead.org
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-xtensa@linux-xtensa.org
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Stafford Horne <shorne@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Richard Henderson <rth@twiddle.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-parisc@vger.kernel.org
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: linux-alpha@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz
2017-08-25 22:49:59 +02:00
Stephan Schreiber 136f39ddc5 Wrong asm register contraints in the futex implementation
The Linux Kernel contains some inline assembly source code which has
wrong asm register constraints in arch/ia64/include/asm/futex.h.

I observed this on Kernel 3.2.23 but it is also true on the most
recent Kernel 3.9-rc1.

File arch/ia64/include/asm/futex.h:

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
			      u32 oldval, u32 newval)
{
	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
		return -EFAULT;

	{
		register unsigned long r8 __asm ("r8");
		unsigned long prev;
		__asm__ __volatile__(
			"	mf;;					\n"
			"	mov %0=r0				\n"
			"	mov ar.ccv=%4;;				\n"
			"[1:]	cmpxchg4.acq %1=[%2],%3,ar.ccv		\n"
			"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"
			"[2:]"
			: "=r" (r8), "=r" (prev)
			: "r" (uaddr), "r" (newval),
			  "rO" ((long) (unsigned) oldval)
			: "memory");
		*uval = prev;
		return r8;
	}
}

The list of output registers is
			: "=r" (r8), "=r" (prev)
The constraint "=r" means that the GCC has to maintain that these vars
are in registers and contain valid info when the program flow leaves
the assembly block (output registers).
But "=r" also means that GCC can put them in registers that are used
as input registers. Input registers are uaddr, newval, oldval on the
example.
The second assembly instruction
			"	mov %0=r0				\n"
is the first one which writes to a register; it sets %0 to 0. %0 means
the first register operand; it is r8 here. (The r0 is read-only and
always 0 on the Itanium; it can be used if an immediate zero value is
needed.)
This instruction might overwrite one of the other registers which are
still needed.
Whether it really happens depends on how GCC decides what registers it
uses and how it optimizes the code.

The objdump utility can give us disassembly.
The futex_atomic_cmpxchg_inatomic() function is inline, so we have to
look for a module that uses the funtion. This is the
cmpxchg_futex_value_locked() function in
kernel/futex.c:

static int cmpxchg_futex_value_locked(u32 *curval, u32 __user *uaddr,
				      u32 uval, u32 newval)
{
	int ret;

	pagefault_disable();
	ret = futex_atomic_cmpxchg_inatomic(curval, uaddr, uval, newval);
	pagefault_enable();

	return ret;
}

Now the disassembly. At first from the Kernel package 3.2.23 which has
been compiled with GCC 4.4, remeber this Kernel seemed to work:
objdump -d linux-3.2.23/debian/build/build_ia64_none_mckinley/kernel/futex.o

0000000000000230 <cmpxchg_futex_value_locked>:
      230:	0b 18 80 1b 18 21 	[MMI]       adds r3=3168,r13;;
      236:	80 40 0d 00 42 00 	            adds r8=40,r3
      23c:	00 00 04 00       	            nop.i 0x0;;
      240:	0b 50 00 10 10 10 	[MMI]       ld4 r10=[r8];;
      246:	90 08 28 00 42 00 	            adds r9=1,r10
      24c:	00 00 04 00       	            nop.i 0x0;;
      250:	09 00 00 00 01 00 	[MMI]       nop.m 0x0
      256:	00 48 20 20 23 00 	            st4 [r8]=r9
      25c:	00 00 04 00       	            nop.i 0x0;;
      260:	08 10 80 06 00 21 	[MMI]       adds r2=32,r3
      266:	00 00 00 02 00 00 	            nop.m 0x0
      26c:	02 08 f1 52       	            extr.u r16=r33,0,61
      270:	05 40 88 00 08 e0 	[MLX]       addp4 r8=r34,r0
      276:	ff ff 0f 00 00 e0 	            movl r15=0xfffffffbfff;;
      27c:	f1 f7 ff 65
      280:	09 70 00 04 18 10 	[MMI]       ld8 r14=[r2]
      286:	00 00 00 02 00 c0 	            nop.m 0x0
      28c:	f0 80 1c d0       	            cmp.ltu p6,p7=r15,r16;;
      290:	08 40 fc 1d 09 3b 	[MMI]       cmp.eq p8,p9=-1,r14
      296:	00 00 00 02 00 40 	            nop.m 0x0
      29c:	e1 08 2d d0       	            cmp.ltu p10,p11=r14,r33
      2a0:	56 01 10 00 40 10 	[BBB] (p10) br.cond.spnt.few 2e0
<cmpxchg_futex_value_locked+0xb0>
      2a6:	02 08 00 80 21 03 	      (p08) br.cond.dpnt.few 2b0
<cmpxchg_futex_value_locked+0x80>
      2ac:	40 00 00 41       	      (p06) br.cond.spnt.few 2e0
<cmpxchg_futex_value_locked+0xb0>
      2b0:	0a 00 00 00 22 00 	[MMI]       mf;;
      2b6:	80 00 00 00 42 00 	            mov r8=r0
      2bc:	00 00 04 00       	            nop.i 0x0
      2c0:	0b 00 20 40 2a 04 	[MMI]       mov.m ar.ccv=r8;;
      2c6:	10 1a 85 22 20 00 	            cmpxchg4.acq r33=[r33],r35,ar.ccv
      2cc:	00 00 04 00       	            nop.i 0x0;;
      2d0:	10 00 84 40 90 11 	[MIB]       st4 [r32]=r33
      2d6:	00 00 00 02 00 00 	            nop.i 0x0
      2dc:	20 00 00 40       	            br.few 2f0
<cmpxchg_futex_value_locked+0xc0>
      2e0:	09 40 c8 f9 ff 27 	[MMI]       mov r8=-14
      2e6:	00 00 00 02 00 00 	            nop.m 0x0
      2ec:	00 00 04 00       	            nop.i 0x0;;
      2f0:	0b 58 20 1a 19 21 	[MMI]       adds r11=3208,r13;;
      2f6:	20 01 2c 20 20 00 	            ld4 r18=[r11]
      2fc:	00 00 04 00       	            nop.i 0x0;;
      300:	0b 88 fc 25 3f 23 	[MMI]       adds r17=-1,r18;;
      306:	00 88 2c 20 23 00 	            st4 [r11]=r17
      30c:	00 00 04 00       	            nop.i 0x0;;
      310:	11 00 00 00 01 00 	[MIB]       nop.m 0x0
      316:	00 00 00 02 00 80 	            nop.i 0x0
      31c:	08 00 84 00       	            br.ret.sptk.many b0;;

The lines
      2b0:	0a 00 00 00 22 00 	[MMI]       mf;;
      2b6:	80 00 00 00 42 00 	            mov r8=r0
      2bc:	00 00 04 00       	            nop.i 0x0
      2c0:	0b 00 20 40 2a 04 	[MMI]       mov.m ar.ccv=r8;;
      2c6:	10 1a 85 22 20 00 	            cmpxchg4.acq r33=[r33],r35,ar.ccv
      2cc:	00 00 04 00       	            nop.i 0x0;;
are the instructions of the assembly block.
The line
      2b6:	80 00 00 00 42 00 	            mov r8=r0
sets the r8 register to 0 and after that
      2c0:	0b 00 20 40 2a 04 	[MMI]       mov.m ar.ccv=r8;;
prepares the 'oldvalue' for the cmpxchg but it takes it from r8. This
is wrong.
What happened here is what I explained above: An input register is
overwritten which is still needed.
The register operand constraints in futex.h are wrong.

(The problem doesn't occur when the Kernel is compiled with GCC 4.6.)

The attached patch fixes the register operand constraints in futex.h.
The code after patching of it:

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
			      u32 oldval, u32 newval)
{
	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
		return -EFAULT;

	{
		register unsigned long r8 __asm ("r8") = 0;
		unsigned long prev;
		__asm__ __volatile__(
			"	mf;;					\n"
			"	mov ar.ccv=%4;;				\n"
			"[1:]	cmpxchg4.acq %1=[%2],%3,ar.ccv		\n"
			"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"
			"[2:]"
			: "+r" (r8), "=&r" (prev)
			: "r" (uaddr), "r" (newval),
			  "rO" ((long) (unsigned) oldval)
			: "memory");
		*uval = prev;
		return r8;
	}
}

I also initialized the 'r8' var with the C programming language.
The _asm qualifier on the definition of the 'r8' var forces GCC to use
the r8 processor register for it.
I don't believe that we should use inline assembly for zeroing out a
local variable.
The constraint is
"+r" (r8)
what means that it is both an input register and an output register.
Note that the page fault handler will modify the r8 register which
will be the return value of the function.
The real fix is
"=&r" (prev)
The & means that GCC must not use any of the input registers to place
this output register in.

Patched the Kernel 3.2.23 and compiled it with GCC4.4:

0000000000000230 <cmpxchg_futex_value_locked>:
      230:	0b 18 80 1b 18 21 	[MMI]       adds r3=3168,r13;;
      236:	80 40 0d 00 42 00 	            adds r8=40,r3
      23c:	00 00 04 00       	            nop.i 0x0;;
      240:	0b 50 00 10 10 10 	[MMI]       ld4 r10=[r8];;
      246:	90 08 28 00 42 00 	            adds r9=1,r10
      24c:	00 00 04 00       	            nop.i 0x0;;
      250:	09 00 00 00 01 00 	[MMI]       nop.m 0x0
      256:	00 48 20 20 23 00 	            st4 [r8]=r9
      25c:	00 00 04 00       	            nop.i 0x0;;
      260:	08 10 80 06 00 21 	[MMI]       adds r2=32,r3
      266:	20 12 01 10 40 00 	            addp4 r34=r34,r0
      26c:	02 08 f1 52       	            extr.u r16=r33,0,61
      270:	05 40 00 00 00 e1 	[MLX]       mov r8=r0
      276:	ff ff 0f 00 00 e0 	            movl r15=0xfffffffbfff;;
      27c:	f1 f7 ff 65
      280:	09 70 00 04 18 10 	[MMI]       ld8 r14=[r2]
      286:	00 00 00 02 00 c0 	            nop.m 0x0
      28c:	f0 80 1c d0       	            cmp.ltu p6,p7=r15,r16;;
      290:	08 40 fc 1d 09 3b 	[MMI]       cmp.eq p8,p9=-1,r14
      296:	00 00 00 02 00 40 	            nop.m 0x0
      29c:	e1 08 2d d0       	            cmp.ltu p10,p11=r14,r33
      2a0:	56 01 10 00 40 10 	[BBB] (p10) br.cond.spnt.few 2e0
<cmpxchg_futex_value_locked+0xb0>
      2a6:	02 08 00 80 21 03 	      (p08) br.cond.dpnt.few 2b0
<cmpxchg_futex_value_locked+0x80>
      2ac:	40 00 00 41       	      (p06) br.cond.spnt.few 2e0
<cmpxchg_futex_value_locked+0xb0>
      2b0:	0b 00 00 00 22 00 	[MMI]       mf;;
      2b6:	00 10 81 54 08 00 	            mov.m ar.ccv=r34
      2bc:	00 00 04 00       	            nop.i 0x0;;
      2c0:	09 58 8c 42 11 10 	[MMI]       cmpxchg4.acq r11=[r33],r35,ar.ccv
      2c6:	00 00 00 02 00 00 	            nop.m 0x0
      2cc:	00 00 04 00       	            nop.i 0x0;;
      2d0:	10 00 2c 40 90 11 	[MIB]       st4 [r32]=r11
      2d6:	00 00 00 02 00 00 	            nop.i 0x0
      2dc:	20 00 00 40       	            br.few 2f0
<cmpxchg_futex_value_locked+0xc0>
      2e0:	09 40 c8 f9 ff 27 	[MMI]       mov r8=-14
      2e6:	00 00 00 02 00 00 	            nop.m 0x0
      2ec:	00 00 04 00       	            nop.i 0x0;;
      2f0:	0b 88 20 1a 19 21 	[MMI]       adds r17=3208,r13;;
      2f6:	30 01 44 20 20 00 	            ld4 r19=[r17]
      2fc:	00 00 04 00       	            nop.i 0x0;;
      300:	0b 90 fc 27 3f 23 	[MMI]       adds r18=-1,r19;;
      306:	00 90 44 20 23 00 	            st4 [r17]=r18
      30c:	00 00 04 00       	            nop.i 0x0;;
      310:	11 00 00 00 01 00 	[MIB]       nop.m 0x0
      316:	00 00 00 02 00 80 	            nop.i 0x0
      31c:	08 00 84 00       	            br.ret.sptk.many b0;;

Much better.
There is a
      270:	05 40 00 00 00 e1 	[MLX]       mov r8=r0
which was generated by C code r8 = 0. Below
      2b6:	00 10 81 54 08 00 	            mov.m ar.ccv=r34
what means that oldval is no longer overwritten.

This is Debian bug#702641
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702641).

The patch is applicable on Kernel 3.9-rc1, 3.2.23 and many other versions.

Signed-off-by: Stephan Schreiber <info@fs-driver.org>
Cc: stable@vger.kernel.org
Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-03-19 16:14:53 -07:00
Luck, Tony c76f39bddb ia64: fix futex_atomic_cmpxchg_inatomic()
Michel Lespinasse cleaned up the futex calling conventions in commit
37a9d912b2 ("futex: Sanitize cmpxchg_futex_value_locked API").

But the ia64 implementation was subtly broken.  Gcc does not know that
register "r8" will be updated by the fault handler if the cmpxchg
instruction takes an exception.  So it feels safe in letting the
initialization of r8 slide to after the cmpxchg.  Result: we always
return 0 whether the user address faulted or not.

Fix by moving the initialization of r8 into the __asm__ code so gcc
won't move it.

Reported-by: <emeric.maschino@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42757
Tested-by: <emeric.maschino@gmail.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: stable@vger.kernel.org # v2.6.39+
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-16 18:30:01 -07:00
David Howells c140d87995 Disintegrate asm/system.h for IA64
Disintegrate asm/system.h for IA64.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Tony Luck <tony.luck@intel.com>
cc: linux-ia64@vger.kernel.org
2012-03-28 18:30:02 +01:00
Michel Lespinasse 8d7718aa08 futex: Sanitize futex ops argument types
Change futex_atomic_op_inuser and futex_atomic_cmpxchg_inatomic
prototypes to use u32 types for the futex as this is the data type the
futex core code uses all over the place.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311025058.GD26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:31 +01:00
Michel Lespinasse 37a9d912b2 futex: Sanitize cmpxchg_futex_value_locked API
The cmpxchg_futex_value_locked API was funny in that it returned either
the original, user-exposed futex value OR an error code such as -EFAULT.
This was confusing at best, and could be a source of livelocks in places
that retry the cmpxchg_futex_value_locked after trying to fix the issue
by running fault_in_user_writeable().
    
This change makes the cmpxchg_futex_value_locked API more similar to the
get_futex_value_locked one, returning an error code and updating the
original value through a reference argument.
    
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [tile]
Acked-by: Tony Luck <tony.luck@intel.com>  [ia64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>  [microblaze]
Acked-by: David Howells <dhowells@redhat.com> [frv]
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:08 +01:00
Tony Luck 7f30491ccd [IA64] Move include/asm-ia64 to arch/ia64/include/asm
After moving the the include files there were a few clean-ups:

1) Some files used #include <asm-ia64/xyz.h>, changed to <asm/xyz.h>

2) Some comments alerted maintainers to look at various header files to
make matching updates if certain code were to be changed. Updated these
comments to use the new include paths.

3) Some header files mentioned their own names in initial comments. Just
deleted these self references.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-08-01 10:21:21 -07:00