# git rev-parse -q --verify ab6f762f0f53162d41497708b33c9a3236d3609e^{commit}
ab6f762f0f53162d41497708b33c9a3236d3609e
already have revision, skipping fetch
# git checkout -q -f -B kisskb ab6f762f0f53162d41497708b33c9a3236d3609e
# git clean -qxdf
# < git log -1
# commit ab6f762f0f53162d41497708b33c9a3236d3609e
# Author: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
# Date:   Tue Mar 3 20:30:02 2020 +0900
# 
#     printk: queue wake_up_klogd irq_work only if per-CPU areas are ready
#     
#     printk_deferred(), similarly to printk_safe/printk_nmi, does not
#     immediately attempt to print a new message on the consoles, avoiding
#     calls into non-reentrant kernel paths, e.g. scheduler or timekeeping,
#     which potentially can deadlock the system.
#     
#     Those printk() flavors, instead, rely on per-CPU flush irq_work to print
#     messages from safer contexts.  For same reasons (recursive scheduler or
#     timekeeping calls) printk() uses per-CPU irq_work in order to wake up
#     user space syslog/kmsg readers.
#     
#     However, only printk_safe/printk_nmi do make sure that per-CPU areas
#     have been initialised and that it's safe to modify per-CPU irq_work.
#     This means that, for instance, should printk_deferred() be invoked "too
#     early", that is before per-CPU areas are initialised, printk_deferred()
#     will perform illegal per-CPU access.
#     
#     Lech Perczak [0] reports that after commit 1b710b1b10ef ("char/random:
#     silence a lockdep splat with printk()") user-space syslog/kmsg readers
#     are not able to read new kernel messages.
#     
#     The reason is printk_deferred() being called too early (as was pointed
#     out by Petr and John).
#     
#     Fix printk_deferred() and do not queue per-CPU irq_work before per-CPU
#     areas are initialized.
#     
#     Link: https://lore.kernel.org/lkml/aa0732c6-5c4e-8a8b-a1c1-75ebe3dca05b@camlintechnologies.com/
#     Reported-by: Lech Perczak <l.perczak@camlintechnologies.com>
#     Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
#     Tested-by: Jann Horn <jannh@google.com>
#     Reviewed-by: Petr Mladek <pmladek@suse.com>
#     Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#     Cc: Theodore Ts'o <tytso@mit.edu>
#     Cc: John Ogness <john.ogness@linutronix.de>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version
# < git log --format=%s --max-count=1 ab6f762f0f53162d41497708b33c9a3236d3609e
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/linus_mpc885_ads_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  mpc885_ads_defconfig
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/linus_mpc885_ads_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  help
# make -s -j 32 ARCH=powerpc O=/kisskb/build/linus_mpc885_ads_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  olddefconfig
# make -s -j 32 ARCH=powerpc O=/kisskb/build/linus_mpc885_ads_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:471:21: note: 'pdeo' was declared here
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c: In function 'handle_dots':
/kisskb/src/fs/namei.c:1805:10: warning: 'inode' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c:1805:10: warning: 'seq' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update.isra.90':
/kisskb/src/fs/io_uring.c:6673:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
Image Name:   Linux-5.6.0-gab6f762f0f53
Created:      Sat Apr 11 07:36:46 2020
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    1795249 Bytes = 1753.17 KiB = 1.71 MiB
Load Address: 00400000
Entry Point:  004001dc
Completed OK
# rm -rf /kisskb/build/linus_mpc885_ads_defconfig_powerpc-gcc4.6
# Build took: 0:00:42.810536