On Mon, Apr 24, 2017 at 6:53 PM, Maciej W. Rozycki <macro@xxxxxxxxxxxxxx> wrote: > On Mon, 24 Apr 2017, Arnd Bergmann wrote: > >> > If there's no real good reason (brokenness) to deprecate gcc-4.1, I would not >> > do it.I guess most people using old compilers know what they're doing. >> >> What I'm trying to find out first is whether "people regularly using 10+ >> year old compilers for the latest kernels" is a strict subset of "people in >> Geert's household". > > Well I do not live with Geert TBH. Sorry about that, you had mentioned that you had used it recently, which should have weighed more than my own results. > Linux 4.11-rc8 > $ /usr/bin/time make ARCH=mips CROSS_COMPILE=mipsel-linux- decstation_defconfig vmlinux >/dev/null 2>&1 > 1014.19user 71.47system 19:33.24elapsed 92%CPU (0avgtext+0avgdata > 0maxresident)k18764inputs+242504outputs (704major+9549837minor)pagefaults 0swaps > $ mipsel-linux-gcc --version > gcc (GCC) 4.1.2 > Copyright (C) 2006 Free Software Foundation, Inc. > This is free software; see the source for copying conditions. There is NO > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > $ > > Methinks it builds just fine. I must have done something wrong: I tried a few defconfigs with a latest kernel and compiler and they all failed, found linux-4.3 to be the first version that was broken for all of them (most with a link time error, some with missing gcc features) I later tried all mips defconfigs with linux-4.3 and they all failed with gcc-4.1.3 but built fine with gcc-4.9. I've now tried decstation_defconfig in 4.8-rc11, and this is what I see for gcc-4.1.3 make O=build/mips/decstation_defconfig/ -skj30 CC=/home/arnd/cross-gcc/bin/mips-linux-gcc-4.1.3\ ARCH=mips -f Makefile CROSS_COMPILE=/home/arnd/cross-gcc/bin/mips-linux- /git/arm-soc/fs/dcache.c: In function '__d_move': /git/arm-soc/fs/dcache.c:2773: warning: 'n' may be used uninitialized in this function /git/arm-soc/fs/dcache.c: In function 'd_splice_alias': /git/arm-soc/fs/dcache.c:2529: warning: 'n' may be used uninitialized in this function /git/arm-soc/fs/dcache.c: In function 'd_add': /git/arm-soc/fs/dcache.c:2529: warning: 'n' may be used uninitialized in this function /git/arm-soc/mm/page-writeback.c: In function 'balance_dirty_pages_ratelimited': /git/arm-soc/mm/page-writeback.c:1627: warning: 'writeback' is used uninitialized in this function /git/arm-soc/mm/page-writeback.c:1628: warning: 'filepages' is used uninitialized in this function /git/arm-soc/mm/page-writeback.c:1628: warning: 'headroom' is used uninitialized in this function /git/arm-soc/mm/page-writeback.c: In function 'wb_over_bg_thresh': /git/arm-soc/mm/page-writeback.c:1956: warning: 'filepages' is used uninitialized in this function /git/arm-soc/mm/page-writeback.c:1956: warning: 'headroom' is used uninitialized in this function /git/arm-soc/net/core/flow_dissector.c: In function '__skb_flow_dissect': /git/arm-soc/net/core/flow_dissector.c:272: warning: 'vlan' may be used uninitialized in this function /git/arm-soc/fs/splice.c: In function 'iter_file_splice_write': /git/arm-soc/fs/splice.c:716: warning: 'ret' may be used uninitialized in this function /git/arm-soc/net/core/dev.c: In function 'validate_xmit_skb_list': /git/arm-soc/net/core/dev.c:3003: warning: 'tail' may be used uninitialized in this function /git/arm-soc/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /git/arm-soc/kernel/printk/printk.c:161: warning: 'old' may be used uninitialized in this function /git/arm-soc/kernel/time/ntp.c: In function 'ntp_validate_timex': /git/arm-soc/kernel/time/ntp.c:707: warning: comparison is always false due to limited range of data type /git/arm-soc/kernel/time/ntp.c:709: warning: comparison is always false due to limited range of data type /git/arm-soc/kernel/time/timekeeping.c: In function 'get_device_system_crosststamp': /git/arm-soc/kernel/time/timekeeping.c:1084: warning: 'cs_was_changed_seq' may be used uninitialized in this function /git/arm-soc/net/sunrpc/xdr.c: In function 'xdr_stream_decode_string_dup': /git/arm-soc/include/linux/sunrpc/xdr.h:409: warning: 'len' may be used uninitialized in this function /git/arm-soc/crypto/drbg.c: In function 'drbg_kcapi_random': /git/arm-soc/crypto/drbg.c:1865: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See <URL:http://gcc.gnu.org/bugs.html> for instructions. /git/arm-soc/scripts/Makefile.build:300: recipe for target 'crypto/drbg.o' failed So it still fails, but only because of one compiler error that I can avoid by disabling that driver, and you probably use a slightly patched compiler version that doesn't have this particular bug, or it was a regression between gcc-4.1.2 and 4.1.3. Arnd
