Buildresult: linus/xtensa-defconfig/xtensa-gcc8 built on Apr 11 2020, 09:33

kisskb

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Status:	OK
Date/Time:	Apr 11 2020, 09:33
Duration:	0:00:30.875115
Builder:	ka3
Revision:	printk: queue wake_up_klogd irq_work only if per-CPU areas are ready (`ab6f762f0f53162d41497708b33c9a3236d3609e)`
Target:	linus/xtensa-defconfig/xtensa-gcc8
Branch:	linus
Compiler:	xtensa-gcc8 (xtensa-linux-gcc.br_real (Buildroot 2016.11-git-00613-ge98b4dd) 5.4.0 / GNU ld (GNU Binutils) 2.26.1)
Config:	defconfig (download)
Log:	Download original No warnings found in log. Full Log # 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/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-gcc --version # < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-ld --version # < git log --format=%s --max-count=1 ab6f762f0f53162d41497708b33c9a3236d3609e # < make -s -j 80 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- defconfig # < make -s -j 80 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- help # make -s -j 80 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- olddefconfig # make -s -j 80 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- Completed OK # rm -rf /kisskb/build/linus_xtensa-defconfig_xtensa # Build took: 0:00:30.875115

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