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Dave Martin 0fe42512b2 arm64: Fix syscall restarting around signal suppressed by tracer 
Commit 17c2895 ("arm64: Abstract syscallno manipulation") abstracts
out the pt_regs.syscallno value for a syscall cancelled by a tracer
as NO_SYSCALL, and provides helpers to set and check for this
condition.  However, the way this was implemented has the
unintended side-effect of disabling part of the syscall restart
logic.

This comes about because the second in_syscall() check in
do_signal() re-evaluates the "in a syscall" condition based on the
updated pt_regs instead of the original pt_regs.  forget_syscall()
is explicitly called prior to the second check in order to prevent
restart logic in the ret_to_user path being spuriously triggered,
which means that the second in_syscall() check always yields false.

This triggers a failure in
tools/testing/selftests/seccomp/seccomp_bpf.c, when using ptrace to
suppress a signal that interrups a nanosleep() syscall.

Misbehaviour of this type is only expected in the case where a
tracer suppresses a signal and the target process is either being
single-stepped or the interrupted syscall attempts to restart via
-ERESTARTBLOCK.

This patch restores the old behaviour by performing the
in_syscall() check only once at the start of the function.

Fixes: 17c2895860 ("arm64: Abstract syscallno manipulation")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reported-by: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> # 4.14.x-
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-06-08 13:21:39 +01:00
arch arm64: Fix syscall restarting around signal suppressed by tracer 2018-06-08 13:21:39 +01:00
block blk-mq: fix sysfs inflight counter 2018-04-26 09:02:01 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation arm64: Add 'ssbd' command-line option 2018-05-31 17:34:49 +01:00
drivers Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux 2018-05-31 18:09:38 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs First pull request for 4.17-rc 2018-05-04 20:51:10 -10:00
include ACPI / PPTT: fix build when CONFIG_ACPI_PPTT is not enabled 2018-06-05 18:06:24 +01:00
init Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-06 05:35:23 -10:00
lib swiotlb: fix inversed DMA_ATTR_NO_WARN test 2018-05-02 14:48:55 +02:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm for-linus-20180504 2018-05-04 20:41:44 -10:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-03 18:57:03 -10:00
samples bpf: sockmap sample use clang flag, -target bpf 2018-04-23 23:42:21 +02:00
scripts Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: pcm: Check PCM state at xfern compat ioctl 2018-05-02 08:54:54 +02:00
tools ACPI fix for 4.17-rc4 2018-05-04 05:43:33 -10:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID 2018-05-31 18:00:59 +01:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
Makefile Linux 4.17-rc4 2018-05-06 16:57:38 -10:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.