Buildresult: linus/mpc512x_defconfig/powerpc-gcc4.6 built on Nov 26 2019, 06:17

kisskb

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Status:	OK
Date/Time:	Nov 26 2019, 06:17
Duration:	0:00:46.324459
Builder:	ka1
Revision:	vfs: properly and reliably lock f_pos in fdget_pos() (`0be0ee71816b2b6725e2b4f32ad6726c9d729777)`
Target:	linus/mpc512x_defconfig/powerpc-gcc4.6
Branch:	linus
Compiler:	powerpc-gcc4.6 (powerpc-linux-gcc (GCC) 4.6.3 / GNU ld (GNU Binutils) 2.22)
Config:	mpc512x_defconfig (download)
Log:	Download original Possible warnings (6) kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] drivers/base/regmap/regmap.c:2591:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] drivers/base/regmap/regmap.c:1852:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] drivers/mtd/nand/raw/mpc5121_nfc.c:293:19: warning: unused variable 'mtd' [-Wunused-variable] drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized] 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/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 0be0ee71816b2b6725e2b4f32ad6726c9d729777 # < make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_mpc512x_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- mpc512x_defconfig # make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_mpc512x_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /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/drivers/base/regmap/regmap.c: In function 'regmap_raw_read': /kisskb/src/drivers/base/regmap/regmap.c:2591:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write': /kisskb/src/drivers/base/regmap/regmap.c:1852:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c: In function 'proc_reg_open': /kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c:338:21: note: 'pdeo' was declared here /kisskb/src/drivers/mtd/nand/raw/mpc5121_nfc.c: In function 'ads5121_select_chip': /kisskb/src/drivers/mtd/nand/raw/mpc5121_nfc.c:293:19: warning: unused variable 'mtd' [-Wunused-variable] /kisskb/src/drivers/usb/core/devio.c: In function 'async_completed': /kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized] INFO: Uncompressed kernel (size 0x665920) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x700000) Image Name: Linux-5.4.0-g0be0ee71816b Created: Tue Nov 26 06:18:22 2019 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 3261954 Bytes = 3185.50 KiB = 3.11 MiB Load Address: 00000000 Entry Point: 00000000 Completed OK # rm -rf /kisskb/build/linus_mpc512x_defconfig_powerpc-gcc4.6 # Build took: 0:00:46.324459

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