January 2025 - devel - example.com

[PATCH] libc/string/x86_64: fix p2align max number of bytes to skip
by Marcus Haehnel 27 Feb '25

27 Feb '25

From: Frank Mehnert <frank.mehnert(a)kernkonzept.com> In a .p2align directive, the maximum number of bytes to skip shall be at most the intended alignment minus 1. Certain assemblers warn otherwise: spn.S:97:14: warning: maximum bytes expression exceeds alignment and has no effect .p2align 3,,8 ^ Change-Id: I5ad48f6f3c3036d8d33d3710ed8d5b5a35bf1fea Signed-off-by: Marcus Haehnel <marcus.haehnel(a)kernkonzept.com> --- libc/string/x86_64/strcat.S | 2 +- libc/string/x86_64/strcspn.S | 2 +- libc/string/x86_64/strlen.S | 2 +- libc/string/x86_64/strspn.S | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/libc/string/x86_64/strcat.S b/libc/string/x86_64/strcat.S index 55e09e5f1..209e19062 100644 --- a/libc/string/x86_64/strcat.S +++ b/libc/string/x86_64/strcat.S @@ -106,7 +106,7 @@ ENTRY (BP_SYM (strcat)) /* Align, it is a jump target. */ /* Next 3 insns are 8 bytes total, make sure we decode them in one go */ - .p2align 3,,8 + .p2align 3,,7 3: subq $8,%rax /* correct pointer increment. */ diff --git a/libc/string/x86_64/strcspn.S b/libc/string/x86_64/strcspn.S index 7a06c8867..5ef565db7 100644 --- a/libc/string/x86_64/strcspn.S +++ b/libc/string/x86_64/strcspn.S @@ -94,7 +94,7 @@ L(1): leaq -4(%rdx), %rax /* prepare loop */ /* but it will also align entire function to 16 bytes, */ /* potentially creating largish padding at link time. */ /* We are aligning to 8 bytes instead: */ - .p2align 3,,8 + .p2align 3,,7 L(3): addq $4, %rax /* adjust pointer for full loop round */ diff --git a/libc/string/x86_64/strlen.S b/libc/string/x86_64/strlen.S index 9e84326c2..2fe2f58b2 100644 --- a/libc/string/x86_64/strlen.S +++ b/libc/string/x86_64/strlen.S @@ -102,7 +102,7 @@ ENTRY (strlen) /* Align, it is a jump target. */ /* Next 3 insns are 8 bytes total, make sure we decode them in one go */ - .p2align 3,,8 + .p2align 3,,7 3: subq $8,%rax /* correct pointer increment. */ diff --git a/libc/string/x86_64/strspn.S b/libc/string/x86_64/strspn.S index 366377649..8dc42656b 100644 --- a/libc/string/x86_64/strspn.S +++ b/libc/string/x86_64/strspn.S @@ -89,7 +89,7 @@ L(1): leaq -4(%rdx), %rax /* prepare loop */ /* but it will also align entire function to 16 bytes, */ /* potentially creating largish padding at link time. */ /* We are aligning to 8 bytes instead: */ - .p2align 3,,8 + .p2align 3,,7 L(3): addq $4, %rax /* adjust pointer for full loop round */ -- 2.47.1

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LTP test fstatat01.c FTBFS on Buildroot bootlin-sh4-uclibc toolchain
by Petr Vorel 29 Jan '25

29 Jan '25

Hi all, LTP test fstatat01.c [1] FTBFS on Buildroot bootlin-sh4-uclibc toolchain (uclibc: 1.0.50, kernel headers: 4.19.255). It looks to me that other bootlin uclibc based toolchains are working, therefore it's probably sh4 problem. Looking into include/sys/stat.h in uclibc-ng [2], extern int fstatat (int __fd, ...) definition is guarded only by: # ifdef __REDIRECT_NTH. But in glibc io/sys/stat.h [3] guardes it with # ifdef __USE_TIME64_REDIRECTS added glibc 2.40 a4ed0471d7 ("Always define __USE_TIME_BITS64 when 64 bit time_t is used") which replaced previous __USE_TIME_BITS64 added in in glibc 2.34 47f24c21ee [4] ("y2038: Add support for 64-bit time on legacy ABIs") [5]. Should similar change be added to uclibc-ng? Kind regards, Petr $ cd ~/br-test-pkg/bootlin-sh4-uclibc/build/ltp-testsuite-728759506cbe08612183275b3543007d1c47f7f4/testcases/kernel/syscalls/fstatat $ make V=1 fstatat01 br-test-pkg/bootlin-sh4-uclibc/host/bin/sh4-linux-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2 -I../../../../include -I../../../../include -I../../../../include/old/ -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -g0 -Ibr-test-pkg/bootlin-sh4-uclibc/host/bin/../sh4-buildroot-linux-uclibc/sysroot/usr/include/tirpc -g -O2 -fno-strict-aliasing -pipe -Wall -W -Wold-style-definition -std=gnu99 -L../../../../lib fstatat01.c -Lbr-test-pkg/bootlin-sh4-uclibc/host/bin/../sh4-buildroot-linux-uclibc/sysroot/usr/lib -ltirpc -lfts -lltp -o fstatat01 fstatat01.c:63:5: error: conflicting types for ‘fstatat’; have ‘int(int, const char *, struct stat64 *, int)’ 63 | int fstatat(int dirfd, const char *filename, struct stat64 *statbuf, int flags) | ^~~~~~~ In file included from br-test-pkg/bootlin-sh4-uclibc/host/sh4-buildroot-linux-uclibc/sysroot/usr/include/features.h:409, from br-test-pkg/bootlin-sh4-uclibc/host/sh4-buildroot-linux-uclibc/sysroot/usr/include/sys/types.h:26, from fstatat01.c:27: br-test-pkg/bootlin-sh4-uclibc/host/sh4-buildroot-linux-uclibc/sysroot/usr/include/sys/stat.h:243:12: note: previous declaration of ‘fstatat’ with type ‘int(int, const char * restrict, struct stat * restrict, int)’ 243 | extern int __REDIRECT_NTH (fstatat, (int __fd, const char *__restrict __file, | ^~~~~~~~~~~~~~ [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/sysc… [2] https://cgit.openadk.org/cgi/cgit/uclibc-ng.git/tree/include/sys/stat.h#n247 [3] https://sourceware.org/git/?p=glibc.git;a=blob;f=io/sys/stat.h;h=4bea9e9a77… [4] https://sourceware.org/git/?p=glibc.git;a=commit;h=a4ed0471d71739928a0d0fa3… [5] https://sourceware.org/git/?p=glibc.git;a=commit;h=47f24c21ee38701ae275aa9e…

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error: '__NR__dl_fstat' undeclared, uClibc-ng 1.0.50, headers 4.4
by Thomas Petazzoni 19 Jan '25

19 Jan '25

Hello, uClibc-ng 1.0.50 + Linux headers 4.4 fails to build with: In file included from ./include/sys/syscall.h:33, from ./ldso/include/dl-syscall.h:12, from ./ldso/include/ldso.h:52, from ldso/ldso/ldso.c:32: ./ldso/include/dl-syscall.h: In function '_dl_fstat': ./include/bits/syscalls-common.h:34:63: error: '__NR__dl_fstat' undeclared (first use in this function); did you mean '_dl_fstat'? # define INLINE_SYSCALL(name, nr, args...) INLINE_SYSCALL_NCS(__NR_##name, nr, args) This is reproducible with Buildroot's arcturus_ucp1020_defconfig, and a log is visible at: https://gitlab.com/buildroot.org/buildroot/-/jobs/8864051076 With the full log at: https://buildroot.org.gitlab.io/-/buildroot/-/jobs/8864051076/artifacts/bui… Any clue? Thomas -- Thomas Petazzoni, co-owner and CEO, Bootlin Embedded Linux and Kernel engineering and training https://bootlin.com

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[PATCH] uclibc: prevent warning about setting an unused variable
by Marcus Haehnel 16 Jan '25

16 Jan '25

From: Frank Mehnert <frank.mehnert(a)kernkonzept.com> This variable is used either if __UCLIBC_HAS_FLOATS__ is defined or if __UCLIBC_HAS_GLIBC_DIGIT_GROUPING__ is defined. Instead of adding more complicated #ifdef magic, just mark this variable as possibly unused to satisfy the compiler. Signed-off-by: marcus.haehnel(a)kernkonzept.com --- libc/stdio/_scanf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libc/stdio/_scanf.c b/libc/stdio/_scanf.c index 3f3000d6f..cb72d14ac 100644 --- a/libc/stdio/_scanf.c +++ b/libc/stdio/_scanf.c @@ -1715,7 +1715,7 @@ int attribute_hidden __psfs_do_numeric(psfs_t *psfs, struct scan_cookie *sc) #define MAX_DIGITS 65 /* Allow one leading 0. */ unsigned char buf[MAX_DIGITS+2+ 100]; unsigned char usflag, base; - unsigned char nonzero = 0; + unsigned char nonzero __attribute__((unused)) = 0; unsigned char seendigit = 0; #ifndef __UCLIBC_HAS_FLOATS__ -- 2.47.1

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1.0.51 released
by Waldemar Brodkorb 16 Jan '25

16 Jan '25

Hi uClibc-ng hackers, I released 1.0.51. See here for changes: Dmitry Chestnykh (2): mips64n32, time64: Select correct _dl_fstat impl Revert "mips64: time64 for n32 ABI breaks a lot of tests, disable it for now" Frank Mehnert (4): uclibc: prevent warning about setting an unused variable uclibc: prevent warning about declaring an unused function prevent warning about setting an unused variable fix possible overflow in pointer arithmetics strnlen() Mingxiang Lu (1): fix TLS memory leak with dlopen Nadav Tasher (3): features.h: error out when attempting to compile with TIME64 for 32bit targets on Linux versions prior to 5.1.0 Revert "features.h: error out when attempting to compile with TIME64 for 32bit targets on Linux versions prior to 5.1.0" time64_helpers.h: error out when attempting to compile with TIME64 for 32bit targets on Linux versions prior to 5.1.0 Waldemar Brodkorb (4): add process_vm_{read,write}v syscall wrapper from glibc mips64: time64 for n32 ABI breaks a lot of tests, disable it for now clock_adjtime: warn instead of error out bump version for 1.0.51 release best regards Waldemar

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[PATCH] features.h: error out when attempting to compile with TIME64 for 32bit targets on Linux versions prior to 5.1.0
by Nadav Tasher 13 Jan '25

13 Jan '25

Using 64bit time on 32bit targets was only introduced in Linux 5.1.0. On versions prior to that, compiling uClibc-ng produces incorrect headers that cause the `clock_nanosleep` syscall to receive incorrect arguments. Signed-off-by: Nadav Tasher <tashernadav(a)gmail.com> --- include/features.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/features.h b/include/features.h index 1a4efb9db..0b09d71a2 100644 --- a/include/features.h +++ b/include/features.h @@ -449,6 +449,12 @@ # include <libc-internal.h> #endif +#include <linux/version.h> + +#if defined(__UCLIBC_USE_TIME64__) && __TARGET_ARCH_BITS__ == 32 && LINUX_VERSION_CODE < KERNEL_VERSION(5,1,0) +#error 64bit time on 32bit targets is not supported on Linux < 5.1.0 +#endif + #if defined(__UCLIBC_USE_TIME64__) || __TARGET_ARCH_BITS__ == 64 #define __USE_TIME_BITS64 1 #endif -- 2.34.1

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[PATCH] fix possible overflow in pointer arithmetics strnlen()
by Marcus Haehnel 08 Jan '25

08 Jan '25

From: Frank Mehnert <frank.mehnert(a)kernkonzept.com> It is undefined behavior to compare two pointers belonging to different objects. This includes the case where the addition overflows. Clang-20 seems to follow this rule more eagerly and optimizes away the old test. Fix the test by performing the addition on uintptr_t values rather than on on char pointers. See also https://github.com/llvm/llvm-project/issues/121909. Signed-off-by: Marcus Haehnel <marcus.haehnel(a)kernkonzept.com> --- libc/string/generic/strnlen.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libc/string/generic/strnlen.c b/libc/string/generic/strnlen.c index 4d4cde84f..82d4122ec 100644 --- a/libc/string/generic/strnlen.c +++ b/libc/string/generic/strnlen.c @@ -29,15 +29,17 @@ '\0' terminator is found in that many characters, return MAXLEN. */ size_t strnlen (const char *str, size_t maxlen) { - const char *char_ptr, *end_ptr = str + maxlen; + const char *char_ptr, *end_ptr; const unsigned long int *longword_ptr; unsigned long int longword, himagic, lomagic; if (maxlen == 0) return 0; - if (__builtin_expect (end_ptr < str, 0)) + if (__builtin_expect ((uintptr_t)str + maxlen < (uintptr_t)str, 0)) end_ptr = (const char *) ~0UL; + else + end_ptr = str + maxlen; /* Handle the first few characters by reading one character at a time. Do this until CHAR_PTR is aligned on a longword boundary. */ -- 2.47.1

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[PATCH] prevent warning about setting an unused variable
by Marcus Haehnel 07 Jan '25

07 Jan '25

From: Frank Mehnert <frank.mehnert(a)kernkonzept.com> Signed-off-by: Marcus Haehnel <marcus.haehnel(a)kernkonzept.com> --- libc/misc/internals/reloc_static_pie.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libc/misc/internals/reloc_static_pie.c b/libc/misc/internals/reloc_static_pie.c index cb2c4df87..3bbdef18e 100644 --- a/libc/misc/internals/reloc_static_pie.c +++ b/libc/misc/internals/reloc_static_pie.c @@ -107,6 +107,8 @@ reloc_static_pie(ElfW(Addr) load_addr) PERFORM_BOOTSTRAP_RELOC(rpnt, reloc_addr, symbol_addr, load_addr, sym); } } +#else + (void)rel_size; #endif } _dl_load_base = load_addr; -- 2.47.1

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[PATCH] uclibc: prevent warning about declaring an unused function
by Marcus Haehnel 06 Jan '25

06 Jan '25

From: Frank Mehnert <frank.mehnert(a)kernkonzept.com> Signed-off-by: Marcus Haehnel <marcus.haehnel(a)kernkonzept.com> --- libc/stdlib/stdlib.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libc/stdlib/stdlib.c b/libc/stdlib/stdlib.c index f5936630c..c45dd53a5 100644 --- a/libc/stdlib/stdlib.c +++ b/libc/stdlib/stdlib.c @@ -822,6 +822,7 @@ libc_hidden_def(_stdlib_mb_cur_max) #endif +#if defined(L_mblen) || defined(L_mbtowc) || defined(L_wctomb) #ifdef __UCLIBC_HAS_LOCALE__ /* * The following function return 1 if the encoding is stateful, 0 if stateless. @@ -844,6 +845,7 @@ static __always_inline int is_stateful(unsigned char encoding) #else #define is_stateful(encoding) 0 #endif +#endif /**********************************************************************/ #ifdef L_mblen -- 2.47.1

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