Buildresult: linus-rand/mips-allnoconfig/mips-gcc12 built on Jul 27 2023, 07:14

kisskb

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Status:	OK
Date/Time:	Jul 27 2023, 07:14
Duration:	0:00:21.968056
Builder:	ka4
Revision:	mm: suppress mm fault logging if fatal signal already pending (`5f0bc0b042fc77ff70e14c790abdec960cde4ec1)`
Target:	linus-rand/mips-allnoconfig/mips-gcc12
Branch:	linus-rand
Compiler:	mips-gcc12 (mips-linux-gcc (GCC) 12.2.0 / GNU ld (GNU Binutils) 2.39)
Config:	allnoconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify 5f0bc0b042fc77ff70e14c790abdec960cde4ec1^{commit} 5f0bc0b042fc77ff70e14c790abdec960cde4ec1 already have revision, skipping fetch # git checkout -q -f -B kisskb 5f0bc0b042fc77ff70e14c790abdec960cde4ec1 # git clean -qxdf # < git log -1 # commit 5f0bc0b042fc77ff70e14c790abdec960cde4ec1 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Tue Jul 25 09:38:32 2023 -0700 # # mm: suppress mm fault logging if fatal signal already pending # # Commit eda0047296a1 ("mm: make the page fault mmap locking killable") # intentionally made it much easier to trigger the "page fault fails # because a fatal signal is pending" situation, by having the mmap locking # fail early in that case. # # We have long aborted page faults in other fatal cases when the actual IO # for a page is interrupted by SIGKILL - which is particularly useful for # the traditional case of NFS hanging due to network issues, but local # filesystems could cause it too if you happened to get the SIGKILL while # waiting for a page to be faulted in (eg lock_folio_maybe_drop_mmap()). # # So aborting the page fault wasn't a new condition - but it now triggers # earlier, before we even get to 'handle_mm_fault()'. And as a result the # error doesn't go through our 'fault_signal_pending()' logic, and doesn't # get filtered away there. # # Normally you'd never even notice, because if a fatal signal is pending, # the new SIGSEGV we send ends up being ignored anyway. # # But it turns out that there is one very noticeable exception: if you # enable 'show_unhandled_signals', the aborted page fault will be logged # in the kernel messages, and you'll get a scary line looking something # like this in your logs: # # pverados[2183248]: segfault at 55e5a00f9ae0 ip 000055e5a00f9ae0 sp 00007ffc0720bea8 error 14 in perl[55e5a00d4000+195000] likely on CPU 10 (core 4, socket 0) # # which is rather misleading. It's not really a segfault at all, it's # just "the thread was killed before the page fault completed, so we # aborted the page fault". # # Fix this by just making it clear that a pending fatal signal means that # any new signal coming in after that is implicitly handled. This will # avoid the misleading logging, since now the signal isn't 'unhandled' any # more. # # Reported-and-tested-by: Fiona Ebner <f.ebner@proxmox.com> # Tested-by: Thomas Lamprecht <t.lamprecht@proxmox.com> # Link: https://lore.kernel.org/lkml/8d063a26-43f5-0bb7-3203-c6a04dc159f8@proxmox.com/ # Acked-by: Oleg Nesterov <oleg@redhat.com> # Fixes: eda0047296a1 ("mm: make the page fault mmap locking killable") # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux-ld --version # < git log --format=%s --max-count=1 5f0bc0b042fc77ff70e14c790abdec960cde4ec1 # make -s -j 40 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc12 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux- allnoconfig # < make -s -j 40 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc12 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux- help # make -s -j 40 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc12 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux- olddefconfig # make -s -j 40 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc12 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-12.2.0-nolibc/mips-linux/bin/mips-linux- Completed OK # rm -rf /kisskb/build/linus-rand_allnoconfig_mips-gcc12 # Build took: 0:00:21.968056

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