forked from Minki/linux
mainlining shenanigans
df29a7440c
with generic entry, there's a bug when it comes to restarting of signals. The failing sequence is: a) a signal is coming in, and no handler is registered, so the lower part of arch_do_signal_or_restart() in arch/s390/kernel/signal.c sets PIF_SYSCALL_RESTART. b) a second signal gets pending while the kernel is still in the exit loop, and for that one, a handler exists. c) The first part of arch_do_signal_or_restart() is called. That part calls handle_signal(), which sets up stack + registers for handling the signal. d) __do_syscall() in arch/s390/kernel/syscall.c checks for PIF_SYSCALL_RESTART right before leaving to userspace. If it is set, it restart's the syscall. However, the registers are already setup for handling a signal from c). The syscall is now restarted with the wrong arguments. Change the code to: - use vdso for syscall_restart() instead of PIF_SYSCALL_RESTART because we cannot rewind and go back to userspace on s390 because the system call number might be encoded in the svc instruction. - for all other syscalls we rewind the PSW and return to userspace. Cc: <stable@kernel.org> # v5.12+ |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.