linux_dsm_epyc7002/arch/x86/entry
Will Deacon 784e0300fe rseq: Avoid infinite recursion when delivering SIGSEGV
When delivering a signal to a task that is using rseq, we call into
__rseq_handle_notify_resume() so that the registers pushed in the
sigframe are updated to reflect the state of the restartable sequence
(for example, ensuring that the signal returns to the abort handler if
necessary).

However, if the rseq management fails due to an unrecoverable fault when
accessing userspace or certain combinations of RSEQ_CS_* flags, then we
will attempt to deliver a SIGSEGV. This has the potential for infinite
recursion if the rseq code continuously fails on signal delivery.

Avoid this problem by using force_sigsegv() instead of force_sig(), which
is explicitly designed to reset the SEGV handler to SIG_DFL in the case
of a recursive fault. In doing so, remove rseq_signal_deliver() from the
internal rseq API and have an optional struct ksignal * parameter to
rseq_handle_notify_resume() instead.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: peterz@infradead.org
Cc: paulmck@linux.vnet.ibm.com
Cc: boqun.feng@gmail.com
Link: https://lkml.kernel.org/r/1529664307-983-1-git-send-email-will.deacon@arm.com
2018-06-22 19:04:22 +02:00
..
syscalls x86: Wire up restartable sequence system call 2018-06-06 11:58:32 +02:00
vdso Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 19:16:16 -07:00
vsyscall docs: Fix some broken references 2018-06-15 18:10:01 -03:00
calling.h syscalls/x86: Extend register clearing on syscall entry to lower registers 2018-04-05 16:59:39 +02:00
common.c rseq: Avoid infinite recursion when delivering SIGSEGV 2018-06-22 19:04:22 +02:00
entry_32.S Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
entry_64_compat.S x86/entry/64/compat: Preserve r8-r11 in int $0x80 2018-04-27 17:07:58 +02:00
entry_64.S Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
syscall_32.c syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64 2018-04-05 16:59:38 +02:00
syscall_64.c syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64 2018-04-05 16:59:38 +02:00
thunk_32.S x86: move exports to actual definitions 2016-08-07 23:47:15 -04:00
thunk_64.S x86: move exports to actual definitions 2016-08-07 23:47:15 -04:00