2005-04-16 15:20:36 -07:00
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2012-06-25 17:15:31 +09:00
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2005-05-01 08:59:01 -07:00
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[PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish. The code is derived from arch/powerpc.
The advantages of having common BUG handling are:
- consistent BUG reporting across architectures
- shared implementation of out-of-line file/line data
- implement CONFIG_DEBUG_BUGVERBOSE consistently
This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.
A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it. This extra information is
stored in the __bug_table section in the ELF file.
When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug(). This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information. If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.
Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.
lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries. The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.
Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.
Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.
[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 02:36:19 -08:00
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2008-12-16 11:40:27 +00:00
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|
[PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish. The code is derived from arch/powerpc.
The advantages of having common BUG handling are:
- consistent BUG reporting across architectures
- shared implementation of out-of-line file/line data
- implement CONFIG_DEBUG_BUGVERBOSE consistently
This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.
A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it. This extra information is
stored in the __bug_table section in the ELF file.
When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug(). This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information. If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.
Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.
lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries. The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.
Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.
Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.
[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 02:36:19 -08:00
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|
|
2008-12-16 11:40:27 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish. The code is derived from arch/powerpc.
The advantages of having common BUG handling are:
- consistent BUG reporting across architectures
- shared implementation of out-of-line file/line data
- implement CONFIG_DEBUG_BUGVERBOSE consistently
This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.
A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it. This extra information is
stored in the __bug_table section in the ELF file.
When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug(). This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information. If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.
Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.
lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries. The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.
Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.
Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.
[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 02:36:19 -08:00
|
|
|
|
2008-12-16 11:40:27 +00:00
|
|
|
|
[PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish. The code is derived from arch/powerpc.
The advantages of having common BUG handling are:
- consistent BUG reporting across architectures
- shared implementation of out-of-line file/line data
- implement CONFIG_DEBUG_BUGVERBOSE consistently
This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.
A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it. This extra information is
stored in the __bug_table section in the ELF file.
When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug(). This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information. If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.
Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.
lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries. The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.
Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.
Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.
[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 02:36:19 -08:00
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|
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2008-12-16 11:40:27 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish. The code is derived from arch/powerpc.
The advantages of having common BUG handling are:
- consistent BUG reporting across architectures
- shared implementation of out-of-line file/line data
- implement CONFIG_DEBUG_BUGVERBOSE consistently
This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.
A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it. This extra information is
stored in the __bug_table section in the ELF file.
When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug(). This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information. If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.
Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.
lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries. The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.
Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.
Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.
[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 02:36:19 -08:00
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2009-01-06 14:41:01 -08:00
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2005-04-16 15:20:36 -07:00
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2008-10-15 22:01:24 -07:00
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2005-04-16 15:20:36 -07:00
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2014-04-07 15:39:11 -07:00
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2005-04-16 15:20:36 -07:00
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2009-01-06 14:41:01 -08:00
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2010-04-03 19:34:56 +01:00
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2011-10-31 17:11:33 -07:00
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2009-05-06 16:02:53 -07:00
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2008-01-30 13:32:50 +01:00
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2009-05-06 16:02:53 -07:00
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2010-04-03 19:34:56 +01:00
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2008-07-25 01:45:53 -07:00
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2010-04-03 19:34:56 +01:00
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2008-11-28 17:56:14 +01:00
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2010-04-03 19:34:56 +01:00
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2008-01-30 13:32:50 +01:00
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2016-03-17 14:23:04 -07:00
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2008-01-30 13:32:50 +01:00
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2006-09-29 01:59:06 -07:00
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2007-07-31 21:12:07 -07:00
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2008-01-30 13:32:50 +01:00
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2006-09-29 01:59:06 -07:00
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2005-04-16 15:20:36 -07:00
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2008-07-25 01:45:53 -07:00
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2010-04-03 19:34:56 +01:00
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2006-10-06 00:43:49 -07:00
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2012-03-23 15:01:52 -07:00
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2007-07-31 21:12:07 -07:00
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2006-10-06 00:43:49 -07:00
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2016-03-17 14:21:12 -07:00
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2006-10-06 00:43:49 -07:00
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2006-06-25 05:48:09 -07:00
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2008-09-15 16:43:18 -07:00
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2012-03-23 15:01:52 -07:00
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2008-09-15 16:43:18 -07:00
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2016-03-17 14:21:12 -07:00
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2008-09-15 16:43:18 -07:00
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2010-04-03 19:34:56 +01:00
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2012-03-23 15:01:52 -07:00
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2010-04-03 19:34:56 +01:00
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2016-03-17 14:21:12 -07:00
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2010-04-03 19:34:56 +01:00
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2014-04-07 15:39:10 -07:00
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2014-04-07 15:39:13 -07:00
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2014-04-07 15:39:10 -07:00
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asm-generic: default BUG_ON(x) to if(x)BUG()
When CONFIG_BUG is disabled, BUG_ON() will only evaluate the condition,
but will not actually stop the current thread. GCC warns about a couple
of BUG_ON() users where this actually leads to further undefined
behavior:
include/linux/ceph/osdmap.h: In function 'ceph_can_shift_osds':
include/linux/ceph/osdmap.h:54:1: warning: control reaches end of non-void function
fs/ext4/inode.c: In function 'ext4_map_blocks':
fs/ext4/inode.c:548:5: warning: 'retval' may be used uninitialized in this function
drivers/mfd/db8500-prcmu.c: In function 'prcmu_config_clkout':
drivers/mfd/db8500-prcmu.c:762:10: warning: 'div_mask' may be used uninitialized in this function
drivers/mfd/db8500-prcmu.c:769:13: warning: 'mask' may be used uninitialized in this function
drivers/mfd/db8500-prcmu.c:757:7: warning: 'bits' may be used uninitialized in this function
drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq':
drivers/tty/serial/8250/8250_core.c:252:18: warning: 'i' may be used uninitialized in this function
drivers/tty/serial/8250/8250_core.c:235:19: note: 'i' was declared here
There is an obvious conflict of interest here: on the one hand, someone
who disables CONFIG_BUG() will want the kernel to be as small as possible
and doesn't care about printing error messages to a console that nobody
looks at. On the other hand, running into a BUG_ON() condition means that
something has gone wrong, and we probably want to also stop doing things
that might cause data corruption.
This patch picks the second choice, and changes the NOP to BUG(), which
normally stops the execution of the current thread in some form (endless
loop or a trap). This follows the logic we applied in a4b5d580e078 ("bug:
Make BUG() always stop the machine").
For ARM multi_v7_defconfig, the size slightly increases:
section CONFIG_BUG=y CONFIG_BUG=n CONFIG_BUG=n+patch
.text 8320248 | 8180944 | 8207688
.rodata 3633720 | 3567144 | 3570648
__bug_table 32508 | --- | ---
__modver 692 | 1584 | 2176
.init.text 558132 | 548300 | 550088
.exit.text 12380 | 12256 | 12380
.data 1016672 | 1016064 | 1016128
Total 14622556 | 14374510 | 14407326
So instead of saving 1.70% of the total image size, we only save 1.48%
by turning off CONFIG_BUG, but in return we can ensure that we don't run
into cases of uninitialized variable or return code uses when something
bad happens. Aside from that, we significantly reduce the number of
warnings in randconfig builds, which makes it easier to fix the warnings
about other problems.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2015-11-21 00:27:26 +01:00
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2014-04-07 15:39:10 -07:00
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2014-04-07 15:39:12 -07:00
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2014-04-07 15:39:10 -07:00
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2011-03-17 15:21:06 -04:00
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2006-06-27 02:54:50 -07:00
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2011-03-25 16:21:06 -04:00
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2011-03-17 15:21:06 -04:00
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2006-06-27 02:54:50 -07:00
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2012-06-18 13:54:17 +09:00
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2005-04-16 15:20:36 -07:00
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