It was observed[1] on arm64 that __builtin_strlen led to an infinite
loop in the get_size selftest. This is because __builtin_strlen (and
other builtins) may sometimes result in a call to the C library
function. The C library implementation of strlen uses an IFUNC
resolver to load the most efficient strlen implementation for the
underlying machine and hence has a PLT indirection even for static
binaries. Because this binary avoids the C library startup routines,
the PLT initialization never happens and hence the program gets stuck
in an infinite loop.
On x86_64 the __builtin_strlen just happens to expand inline and avoid
the call but that is not always guaranteed.
Further, while testing on x86_64 (Fedora 31), it was observed that the
test also failed with a segfault inside write() because the generated
code for the write function in glibc seems to access TLS before the
syscall (probably due to the cancellation point check) and fails
because TLS is not initialised.
To mitigate these problems, this patch reduces the interface with the
C library to just the syscall function. The syscall function still
sets errno on failure, which is undesirable but for now it only
affects cases where syscalls fail.
[1] https://bugs.linaro.org/show_bug.cgi?id=5479
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
Reported-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Tested-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Reviewed-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Based on 1 normalized pattern(s):
licensed under the terms of the gnu gpl license version 2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 62 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.929121379@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1. Add the TAP13 header
2. remove variable data from the test description line
3. move the plan count to the end of the file, for consistency with
other kselftests
4. convert memory data from diagnostic (comment) format, to a YAML block
Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
This test shows the amount of memory used by the system.
Note that this is dependent on the user-space that is loaded
when this program runs. Optimally, this program would be
run as the init program itself.
The program is optimized for size itself, to avoid conflating
its own execution with that of the system software.
The code is compiled statically, with no stdlibs. On my x86_64 system,
this results in a statically linked binary of less than 5K.
Signed-off-by: Tim Bird <tim.bird@sonymobile.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Siddhesh Poyarekar