# git rev-parse -q --verify 2e90ca68b0d2f5548804f22f0dd61145516171e3^{commit}
2e90ca68b0d2f5548804f22f0dd61145516171e3
already have revision, skipping fetch
# git checkout -q -f -B kisskb 2e90ca68b0d2f5548804f22f0dd61145516171e3
# git clean -qxdf
# < git log -1
# commit 2e90ca68b0d2f5548804f22f0dd61145516171e3
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Fri Feb 21 12:43:35 2020 -0800
# 
#     floppy: check FDC index for errors before assigning it
#     
#     Jordy Zomer reported a KASAN out-of-bounds read in the floppy driver in
#     wait_til_ready().
#     
#     Which on the face of it can't happen, since as Willy Tarreau points out,
#     the function does no particular memory access.  Except through the FDCS
#     macro, which just indexes a static allocation through teh current fdc,
#     which is always checked against N_FDC.
#     
#     Except the checking happens after we've already assigned the value.
#     
#     The floppy driver is a disgrace (a lot of it going back to my original
#     horrd "design"), and has no real maintainer.  Nobody has the hardware,
#     and nobody really cares.  But it still gets used in virtual environment
#     because it's one of those things that everybody supports.
#     
#     The whole thing should be re-written, or at least parts of it should be
#     seriously cleaned up.  The 'current fdc' index, which is used by the
#     FDCS macro, and which is often shadowed by a local 'fdc' variable, is a
#     prime example of how not to write code.
#     
#     But because nobody has the hardware or the motivation, let's just fix up
#     the immediate problem with a nasty band-aid: test the fdc index before
#     actually assigning it to the static 'fdc' variable.
#     
#     Reported-by: Jordy Zomer <jordy@simplyhacker.com>
#     Cc: Willy Tarreau <w@1wt.eu>
#     Cc: Dan Carpenter <dan.carpenter@oracle.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 2e90ca68b0d2f5548804f22f0dd61145516171e3
# < make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 defconfig
# < make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 help
# make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 olddefconfig
# make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 
/kisskb/src/arch/um/os-Linux/signal.c: In function 'sig_handler_common':
/kisskb/src/arch/um/os-Linux/signal.c:51:1: warning: the frame size of 2960 bytes is larger than 1024 bytes [-Wframe-larger-than=]
 }
 ^
/kisskb/src/arch/um/os-Linux/signal.c: In function 'timer_real_alarm_handler':
/kisskb/src/arch/um/os-Linux/signal.c:95:1: warning: the frame size of 2960 bytes is larger than 1024 bytes [-Wframe-larger-than=]
 }
 ^
  LINK linux
Completed OK
# rm -rf /kisskb/build/linus_um-defconfig_um-x86_64
# Build took: 0:00:49.987386