Buildresult: linus/um-allyesconfig/um-x86_64 built on Mar 5 2019, 15:01

kisskb

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Status:	OK
Date/Time:	Mar 5 2019, 15:01
Duration:	0:07:49.562941
Builder:	ka2
Revision:	fs: Make splice() and tee() take into account O_NONBLOCK flag on pipes (`ee5e001196d1345b8fee25925ff5f1d67936081e)`
Target:	linus/um-allyesconfig/um-x86_64
Branch:	linus
Compiler:	um-x86_64 (x86_64-linux-gcc.br_real (Buildroot 2017.05) 5.4.0 / GNU ld (GNU Binutils) 2.27)
Config:	allyesconfig (download)
Log:	Download original Possible warnings (8) arch/um/kernel/skas/uaccess.c:62:10: warning: unused variable 'buf' [-Wunused-variable] arch/um/os-Linux/umid.c:138:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] arch/um/os-Linux/umid.c:213:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] arch/um/os-Linux/umid.c:388:2: warning: ISO C90 forbids variable length array 'dir' [-Wvla] kernel/bpf/verifier.c:5068:4: warning: 'prev_offset' may be used uninitialized in this function [-Wmaybe-uninitialized] security/apparmor/policy_unpack.c:496:9: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized] lib/lz4/lz4hc_compress.c:579:1: warning: the frame size of 2144 bytes is larger than 2048 bytes [-Wframe-larger-than=] drivers/i2c/i2c-core-base.c:235:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] Full Log # git rev-parse -q --verify ee5e001196d1345b8fee25925ff5f1d67936081e^{commit} ee5e001196d1345b8fee25925ff5f1d67936081e already have revision, skipping fetch # git checkout -q -f -B kisskb ee5e001196d1345b8fee25925ff5f1d67936081e # git clean -qxdf # < git log -1 # commit ee5e001196d1345b8fee25925ff5f1d67936081e # Author: Slavomir Kaslev <kaslevs@vmware.com> # Date: Thu Feb 7 17:45:19 2019 +0200 # # fs: Make splice() and tee() take into account O_NONBLOCK flag on pipes # # The current implementation of splice() and tee() ignores O_NONBLOCK set # on pipe file descriptors and checks only the SPLICE_F_NONBLOCK flag for # blocking on pipe arguments. This is inconsistent since splice()-ing # from/to non-pipe file descriptors does take O_NONBLOCK into # consideration. # # Fix this by promoting O_NONBLOCK, when set on a pipe, to # SPLICE_F_NONBLOCK. # # Some context for how the current implementation of splice() leads to # inconsistent behavior. In the ongoing work[1] to add VM tracing # capability to trace-cmd we stream tracing data over named FIFOs or # vsockets from guests back to the host. # # When we receive SIGINT from user to stop tracing, we set O_NONBLOCK on # the input file descriptor and set SPLICE_F_NONBLOCK for the next call to # splice(). If splice() was blocked waiting on data from the input FIFO, # after SIGINT splice() restarts with the same arguments (no # SPLICE_F_NONBLOCK) and blocks again instead of returning -EAGAIN when no # data is available. # # This differs from the splice() behavior when reading from a vsocket or # when we're doing a traditional read()/write() loop (trace-cmd's # --nosplice argument). # # With this patch applied we get the same behavior in all situations after # setting O_NONBLOCK which also matches the behavior of doing a # read()/write() loop instead of splice(). # # This change does have potential of breaking users who don't expect # EAGAIN from splice() when SPLICE_F_NONBLOCK is not set. OTOH programs # that set O_NONBLOCK and don't anticipate EAGAIN are arguably buggy[2]. # # [1] https://github.com/skaslev/trace-cmd/tree/vsock # [2] https://github.com/torvalds/linux/blob/d47e3da1759230e394096fd742aad423c291ba48/fs/read_write.c#L1425 # # Signed-off-by: Slavomir Kaslev <kaslevs@vmware.com> # Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 ee5e001196d1345b8fee25925ff5f1d67936081e # < make -s -j 8 ARCH=um O=/kisskb/build/linus_um-allyesconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 allyesconfig # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_KCOV=n # Added to kconfig CONFIG_GCC_PLUGINS=n # Added to kconfig CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=n # Added to kconfig CONFIG_GCC_PLUGIN_SANCOV=n # Added to kconfig CONFIG_GCC_PLUGIN_LATENT_ENTROPY=n # Added to kconfig CONFIG_GCC_PLUGIN_STRUCTLEAK=n # Added to kconfig CONFIG_GCC_PLUGIN_RANDSTRUCT=n # Added to kconfig CONFIG_UML_NET=n # Added to kconfig CONFIG_UML_NET_ETHERTAP=n # Added to kconfig CONFIG_UML_NET_TUNTAP=n # Added to kconfig CONFIG_UML_NET_SLIP=n # Added to kconfig CONFIG_UML_NET_DAEMON=n # Added to kconfig CONFIG_UML_NET_VDE=n # Added to kconfig CONFIG_UML_NET_MCAST=n # Added to kconfig CONFIG_UML_NET_PCAP=n # Added to kconfig CONFIG_UML_NET_SLIRP=n # Added to kconfig CONFIG_GCOV_KERNEL=n # yes \n \| make -s -j 8 ARCH=um O=/kisskb/build/linus_um-allyesconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 oldconfig yes: standard output: Broken pipe # make -s -j 8 ARCH=um O=/kisskb/build/linus_um-allyesconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 /kisskb/src/arch/um/kernel/skas/uaccess.c: In function 'do_op_one_page': /kisskb/src/arch/um/kernel/skas/uaccess.c:62:10: warning: unused variable 'buf' [-Wunused-variable] jmp_buf buf; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'is_umdir_used': /kisskb/src/arch/um/os-Linux/umid.c:138:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'create_pid_file': /kisskb/src/arch/um/os-Linux/umid.c:213:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'remove_umid_dir': /kisskb/src/arch/um/os-Linux/umid.c:388:2: warning: ISO C90 forbids variable length array 'dir' [-Wvla] char dir[strlen(uml_dir) + UMID_LEN + 1], err; ^ /kisskb/src/kernel/bpf/verifier.c: In function 'check_btf_info': /kisskb/src/kernel/bpf/verifier.c:5068:4: warning: 'prev_offset' may be used uninitialized in this function [-Wmaybe-uninitialized] verbose(env, ^ /kisskb/src/kernel/bpf/verifier.c:5003:38: note: 'prev_offset' was declared here u32 i, nfuncs, urec_size, min_size, prev_offset; ^ /kisskb/src/security/apparmor/policy_unpack.c: In function 'unpack_trans_table': /kisskb/src/security/apparmor/policy_unpack.c:496:9: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized] str[pos] = ':'; ^ /kisskb/src/lib/lz4/lz4hc_compress.c: In function 'LZ4HC_compress_generic': /kisskb/src/lib/lz4/lz4hc_compress.c:579:1: warning: the frame size of 2144 bytes is larger than 2048 bytes [-Wframe-larger-than=] } ^ /kisskb/src/drivers/i2c/i2c-core-base.c: In function 'i2c_generic_scl_recovery': /kisskb/src/drivers/i2c/i2c-core-base.c:235:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] if (ret == -EOPNOTSUPP) ^ LINK linux Completed OK # rm -rf /kisskb/build/linus_um-allyesconfig_um-x86_64 # Build took: 0:07:49.562941

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