Explicitly truncate the second operand of do_div() to 32 bits to guard
against bogus code calling it with a 64-bit divisor.
[Thorsten]
After upgrading from 3.2 to 3.10, mounting a btrfs volume fails with:
btrfs: setting nodatacow, compression disabled
btrfs: enabling auto recovery
btrfs: disk space caching is enabled
*** ZERO DIVIDE *** FORMAT=2
Current process id is 722
BAD KERNEL TRAP: 00000000
Modules linked in: evdev mac_hid ext4 crc16 jbd2 mbcache btrfs xor lzo_compress zlib_deflate raid6_pq crc32c libcrc32c
PC: [<319535b2>] __btrfs_map_block+0x11c/0x119a [btrfs]
SR: 2000 SP: 30c1fab4 a2: 30f0faf0
d0: 00000000 d1: 00001000 d2: 00000000 d3: 00000000
d4: 00010000 d5: 00000000 a0: 3085c72c a1: 3085c72c
Process mount (pid: 722, task=30f0faf0)
Frame format=2 instr addr=319535ae
Stack from 30c1faec:
00000000 00000020 00000000 00001000 00000000 01401000 30253928 300ffc00
00a843ac 3026f640 00000000 00010000 0009e250 00d106c0 00011220 00000000
00001000 301c6830 0009e32a 000000ff 00000009 3085c72c 00000000 00000000
30c1fd14 00000000 00000020 00000000 30c1fd14 0009e26c 00000020 00000003
00000000 0009dd8a 300b0b6c 30253928 00a843ac 00001000 00000000 00000000
0000a008 3194e76a 30253928 00a843ac 00001000 00000000 00000000 00000002
Call Trace: [<00001000>] kernel_pg_dir+0x0/0x1000
[...]
Code: 222e ff74 2a2e ff5c 2c2e ff60 4c45 1402 <2d40> ff64 2d41 ff68 2205 4c2e 1800 ff68 4c04 0800 2041 d1c0 2206 4c2e 1400 ff68
[Geert]
As diagnosed by Andreas, fs/btrfs/volumes.c:__btrfs_map_block()
calls
do_div(stripe_nr, stripe_len);
with stripe_len u64, while do_div() assumes the divisor is a 32-bit number.
Due to the lack of truncation in the m68k-specific implementation of
do_div(), the division is performed using the upper 32-bit word of
stripe_len, which is zero.
This was introduced by commit 53b381b3ab
("Btrfs: RAID5 and RAID6"), which changed the divisor from
map->stripe_len (struct map_lookup.stripe_len is int) to a 64-bit temporary.
Reported-by: Thorsten Glaser <tg@debian.org>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Tested-by: Thorsten Glaser <tg@debian.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
The traditional 68000 processors and the newer reduced instruction set
ColdFire processors do not support the 32*32->64 multiply or the 64/32->32
divide instructions. This is not a difference based on the presence of
a hardware MMU or not.
Create a new config symbol to mark that a CPU type doesn't support the
longer multiply/divide instructions. Use this then as a basis for using
the fast 64bit based divide (in div64.h) and for linking in the extra
libgcc functions that may be required (mulsi3, divsi3, etc).
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Trivial merge of the mmu and non-mmu versions of div64.h
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Merge header files for m68k and m68knommu to the single location:
arch/m68k/include/asm
The majority of this patch was the result of the
script that is included in the changelog below.
The script was originally written by Arnd Bergman and
exten by me to cover a few more files.
When the header files differed the script uses the following:
The original m68k file is named <file>_mm.h [mm for memory manager]
The m68knommu file is named <file>_no.h [no for no memory manager]
The files uses the following include guard:
This include gaurd works as the m68knommu toolchain set
the __uClinux__ symbol - so this should work in userspace too.
Merging the header files for m68k and m68knommu exposes the
(unexpected?) ABI differences thus it is easier to actually
identify these and thus to fix them.
The commit has been build tested with both a m68k and
a m68knommu toolchain - with success.
The commit has also been tested with "make headers_check"
and this patch fixes make headers_check for m68knommu.
The script used:
TARGET=arch/m68k/include/asm
SOURCE=arch/m68knommu/include/asm
INCLUDE="cachectl.h errno.h fcntl.h hwtest.h ioctls.h ipcbuf.h \
linkage.h math-emu.h md.h mman.h movs.h msgbuf.h openprom.h \
oplib.h poll.h posix_types.h resource.h rtc.h sembuf.h shmbuf.h \
shm.h shmparam.h socket.h sockios.h spinlock.h statfs.h stat.h \
termbits.h termios.h tlb.h types.h user.h"
EQUAL="auxvec.h cputime.h device.h emergency-restart.h futex.h \
ioctl.h irq_regs.h kdebug.h local.h mutex.h percpu.h \
sections.h topology.h"
NOMUUFILES="anchor.h bootstd.h coldfire.h commproc.h dbg.h \
elia.h flat.h m5206sim.h m520xsim.h m523xsim.h m5249sim.h \
m5272sim.h m527xsim.h m528xsim.h m5307sim.h m532xsim.h \
m5407sim.h m68360_enet.h m68360.h m68360_pram.h m68360_quicc.h \
m68360_regs.h MC68328.h MC68332.h MC68EZ328.h MC68VZ328.h \
mcfcache.h mcfdma.h mcfmbus.h mcfne.h mcfpci.h mcfpit.h \
mcfsim.h mcfsmc.h mcftimer.h mcfuart.h mcfwdebug.h \
nettel.h quicc_simple.h smp.h"
FILES="atomic.h bitops.h bootinfo.h bug.h bugs.h byteorder.h cache.h \
cacheflush.h checksum.h current.h delay.h div64.h \
dma-mapping.h dma.h elf.h entry.h fb.h fpu.h hardirq.h hw_irq.h io.h \
irq.h kmap_types.h machdep.h mc146818rtc.h mmu.h mmu_context.h \
module.h page.h page_offset.h param.h pci.h pgalloc.h \
pgtable.h processor.h ptrace.h scatterlist.h segment.h \
setup.h sigcontext.h siginfo.h signal.h string.h system.h swab.h \
thread_info.h timex.h tlbflush.h traps.h uaccess.h ucontext.h \
unaligned.h unistd.h"
mergefile() {
BASE=${1%.h}
git mv ${SOURCE}/$1 ${TARGET}/${BASE}_no.h
git mv ${TARGET}/$1 ${TARGET}/${BASE}_mm.h
cat << EOF > ${TARGET}/$1
EOF
git add ${TARGET}/$1
}
set -e
mkdir -p ${TARGET}
git mv include/asm-m68k/* ${TARGET}
rmdir include/asm-m68k
git rm ${SOURCE}/Kbuild
for F in $INCLUDE $EQUAL; do
git rm ${SOURCE}/$F
done
for F in $NOMUUFILES; do
git mv ${SOURCE}/$F ${TARGET}/$F
done
for F in $FILES ; do
mergefile $F
done
rmdir arch/m68knommu/include/asm
rmdir arch/m68knommu/include
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
