linux_dsm_epyc7002/arch/arm64/mm
Mark Rutland 289d07a2dc arm64: mm: abort uaccess retries upon fatal signal
When there's a fatal signal pending, arm64's do_page_fault()
implementation returns 0. The intent is that we'll return to the
faulting userspace instruction, delivering the signal on the way.

However, if we take a fatal signal during fixing up a uaccess, this
results in a return to the faulting kernel instruction, which will be
instantly retried, resulting in the same fault being taken forever. As
the task never reaches userspace, the signal is not delivered, and the
task is left unkillable. While the task is stuck in this state, it can
inhibit the forward progress of the system.

To avoid this, we must ensure that when a fatal signal is pending, we
apply any necessary fixup for a faulting kernel instruction. Thus we
will return to an error path, and it is up to that code to make forward
progress towards delivering the fatal signal.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Steve Capper <steve.capper@arm.com>
Tested-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-08-22 18:15:42 +01:00
..
cache.S arm64: don't pull uaccess.h into *.S 2016-12-26 13:05:17 -05:00
context.c arm64: cache: Remove support for ASID-tagged VIVT I-caches 2017-03-20 16:16:57 +00:00
copypage.c arm64: Defer dcache flush in __cpu_copy_user_page 2015-12-17 11:07:13 +00:00
dma-mapping.c dma-coherent: introduce interface for default DMA pool 2017-07-20 16:09:10 +02:00
dump.c arm64: dump: Add checking for writable and exectuable pages 2016-11-07 18:15:04 +00:00
extable.c arm64: migrate exception table users off module.h and onto extable.h 2016-09-20 09:36:21 +01:00
fault.c arm64: mm: abort uaccess retries upon fatal signal 2017-08-22 18:15:42 +01:00
flush.c arm64: cache: Merge cachetype.h into cache.h 2017-03-20 16:16:59 +00:00
hugetlbpage.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
init.c arm64: kdump: provide /proc/vmcore file 2017-04-05 18:31:38 +01:00
ioremap.c arm64: use is_vmalloc_addr 2017-02-09 13:47:56 +00:00
kasan_init.c arm64/kasan: don't allocate extra shadow memory 2017-07-10 16:32:33 -07:00
Makefile arm64: Add support for CONFIG_DEBUG_VIRTUAL 2017-01-12 15:05:39 +00:00
mmap.c arm64/mmap: properly account for stack randomization in mmap_base 2017-07-12 16:26:03 -07:00
mmu.c arm64: mmu: Place guard page after mapping of kernel image 2017-07-28 10:32:14 +01:00
numa.c arm64/numa: Drop duplicate message 2017-07-20 17:03:53 +01:00
pageattr.c arm64: use set_memory.h header 2017-05-08 17:15:13 -07:00
pgd.c arm64: mm: drop fixup_init() and mm.h 2016-09-06 19:09:38 +01:00
physaddr.c arm64: Add support for CONFIG_DEBUG_VIRTUAL 2017-01-12 15:05:39 +00:00
proc.S arm64: Avoid clobbering mm in erratum workaround on QDF2400 2017-02-24 10:55:31 +00:00
ptdump_debugfs.c arm64: dump: Make ptdump debugfs a separate option 2016-11-07 18:15:04 +00:00