Buildresult: linus/mips-defconfig/mipsel-gcc5 built on Nov 26 2019, 07:04

kisskb

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Status:	OK
Date/Time:	Nov 26 2019, 07:04
Duration:	0:01:02.244151
Builder:	ka4
Revision:	vfs: properly and reliably lock f_pos in fdget_pos() (`0be0ee71816b2b6725e2b4f32ad6726c9d729777)`
Target:	linus/mips-defconfig/mipsel-gcc5
Branch:	linus
Compiler:	mipsel-gcc5 (mipsel-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 0be0ee71816b2b6725e2b4f32ad6726c9d729777^{commit} 0be0ee71816b2b6725e2b4f32ad6726c9d729777 already have revision, skipping fetch # git checkout -q -f -B kisskb 0be0ee71816b2b6725e2b4f32ad6726c9d729777 # git clean -qxdf # < git log -1 # commit 0be0ee71816b2b6725e2b4f32ad6726c9d729777 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Mon Nov 11 15:51:03 2019 -0800 # # vfs: properly and reliably lock f_pos in fdget_pos() # # fdget_pos() is used by file operations that will read and update f_pos: # things like "read()", "write()" and "lseek()" (but not, for example, # "pread()/pwrite" that get their file positions elsewhere). # # However, it had two separate escape clauses for this, because not # everybody wants or needs serialization of the file position. # # The first and most obvious case is the "file descriptor doesn't have a # position at all", ie a stream-like file. Except we didn't actually use # FMODE_STREAM, but instead used FMODE_ATOMIC_POS. The reason for that # was that FMODE_STREAM didn't exist back in the days, but also that we # didn't want to mark all the special cases, so we only marked the ones # that _required_ position atomicity according to POSIX - regular files # and directories. # # The case one was intentionally lazy, but now that we _do_ have # FMODE_STREAM we could and should just use it. With the change to use # FMODE_STREAM, there are no remaining uses for FMODE_ATOMIC_POS, and all # the code to set it is deleted. # # Any cases where we don't want the serialization because the driver (or # subsystem) doesn't use the file position should just be updated to do # "stream_open()". We've done that for all the obvious and common # situations, we may need a few more. Quoting Kirill Smelkov in the # original FMODE_STREAM thread (see link below for full email): # # "And I appreciate if people could help at least somehow with "getting # rid of mixed case entirely" (i.e. always lock f_pos_lock on # !FMODE_STREAM), because this transition starts to diverge from my # particular use-case too far. To me it makes sense to do that # transition as follows: # # - convert nonseekable_open -> stream_open via stream_open.cocci; # - audit other nonseekable_open calls and convert left users that # truly don't depend on position to stream_open; # - extend stream_open.cocci to analyze alloc_file_pseudo as well (this # will cover pipes and sockets), or maybe convert pipes and sockets # to FMODE_STREAM manually; # - extend stream_open.cocci to analyze file_operations that use # no_llseek or noop_llseek, but do not use nonseekable_open or # alloc_file_pseudo. This might find files that have stream semantic # but are opened differently; # - extend stream_open.cocci to analyze file_operations whose # .read/.write do not use ppos at all (independently of how file was # opened); # - ... # - after that remove FMODE_ATOMIC_POS and always take f_pos_lock if # !FMODE_STREAM; # - gather bug reports for deadlocked read/write and convert missed # cases to FMODE_STREAM, probably extending stream_open.cocci along # the road to catch similar cases # # i.e. always take f_pos_lock unless a file is explicitly marked as # being stream, and try to find and cover all files that are streams" # # We have not done the "extend stream_open.cocci to analyze # alloc_file_pseudo" as well, but the previous commit did manually handle # the case of pipes and sockets. # # The other case where we can avoid locking f_pos is the "this file # descriptor only has a single user and it is us, and thus there is no # need to lock it". # # The second test was correct, although a bit subtle and worth just # re-iterating here. There are two kinds of other sources of references # to the same file descriptor: file descriptors that have been explicitly # shared across fork() or with dup(), and file tables having elevated # reference counts due to threading (or explicit file sharing with # clone()). # # The first case would have incremented the file count explicitly, and in # the second case the previous __fdget() would have incremented it for us # and set the FDPUT_FPUT flag. # # But in both cases the file count would be greater than one, so the # "file_count(file) > 1" test catches both situations. Also note that if # file_count is 1, that also means that no other thread can have access to # the file table, so there also cannot be races with concurrent calls to # dup()/fork()/clone() that would increment the file count any other way. # # Link: https://lore.kernel.org/linux-fsdevel/20190413184404.GA13490@deco.navytux.spb.ru # Cc: Kirill Smelkov <kirr@nexedi.com> # Cc: Eic Dumazet <edumazet@google.com> # Cc: Al Viro <viro@zeniv.linux.org.uk> # Cc: Alan Stern <stern@rowland.harvard.edu> # Cc: Marco Elver <elver@google.com> # Cc: Andrea Parri <parri.andrea@gmail.com> # Cc: Paul McKenney <paulmck@kernel.org> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-gcc --version # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-ld --version # < git log --format=%s --max-count=1 0be0ee71816b2b6725e2b4f32ad6726c9d729777 # < make -s -j 120 ARCH=mips O=/kisskb/build/linus_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- defconfig # make -s -j 120 ARCH=mips O=/kisskb/build/linus_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- FIT description: Linux 5.4.0-g0be0ee71816b Created: Tue Nov 26 07:05:07 2019 Image 0 (kernel@0) Description: Linux 5.4.0-g0be0ee71816b Created: Tue Nov 26 07:05:07 2019 Type: Kernel Image Compression: gzip compressed Data Size: 4788808 Bytes = 4676.57 KiB = 4.57 MiB Architecture: MIPS OS: Linux Load Address: 0x80100000 Entry Point: 0x808d60f0 Hash algo: sha1 Hash value: 86e750f49d6402cf3d434d961ff79309255e1332 Image 1 (fdt@boston) Description: img,boston Device Tree Created: Tue Nov 26 07:05:07 2019 Type: Flat Device Tree Compression: uncompressed Data Size: 3793 Bytes = 3.70 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 4799f50d688573234da6e9d7701234d394759ef4 Image 2 (fdt@ni169445) Description: NI 169445 device tree Created: Tue Nov 26 07:05:07 2019 Type: Flat Device Tree Compression: uncompressed Data Size: 1871 Bytes = 1.83 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 51b89b31605ee62038c8468c429af091dfc75ec7 Image 3 (fdt@ocelot_pcb123) Description: MSCC Ocelot PCB123 Device Tree Created: Tue Nov 26 07:05:07 2019 Type: Flat Device Tree Compression: uncompressed Data Size: 4639 Bytes = 4.53 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 018897896b42c41c943aca35a20e4300dba250c8 Image 4 (fdt@ocelot_pcb120) Description: MSCC Ocelot PCB120 Device Tree Created: Tue Nov 26 07:05:07 2019 Type: Flat Device Tree Compression: uncompressed Data Size: 5198 Bytes = 5.08 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 36c7bd0bd79cfc2f7dd6acda6c7996294f4967e6 Image 5 (fdt@xilfpga) Description: MIPSfpga (xilfpga) Device Tree Created: Tue Nov 26 07:05:07 2019 Type: Flat Device Tree Compression: uncompressed Data Size: 2708 Bytes = 2.64 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 63d058b780f65e22da30f0a183433765f1807f1d Default Configuration: 'conf@default' Configuration 0 (conf@default) Description: Generic Linux kernel Kernel: kernel@0 Configuration 1 (conf@boston) Description: Boston Linux kernel Kernel: kernel@0 FDT: fdt@boston Configuration 2 (conf@ni169445) Description: NI 169445 Linux Kernel Kernel: kernel@0 FDT: fdt@ni169445 Configuration 3 (conf@ocelot_pcb123) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb123 Configuration 4 (conf@ocelot_pcb120) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb120 Configuration 5 (conf@xilfpga) Description: MIPSfpga Linux kernel Kernel: kernel@0 FDT: fdt@xilfpga Completed OK # rm -rf /kisskb/build/linus_mips-defconfig_mipsel # Build took: 0:01:02.244151

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