Revision a57b70519d1f7c53be98478623652738e5ac70d5 authored by Liam Howlett on 18 October 2022, 19:17:12 UTC, committed by Andrew Morton on 21 October 2022, 04:27:23 UTC
mmap should return the start address of newly mapped area when successful. On a successful merge of a VMA, the return address was changed and thus was violating that expectation from userspace. This is a restoration of functionality provided by 309d08d9b3a3 (mm/mmap.c: fix mmap return value when vma is merged after call_mmap()). For completeness of fixing MAP_FIXED, implement the comments from the previous discussion to never update the address and fail if the address changes. Leaving the error as a WARN_ON() to avoid crashing the kernel. Link: https://lkml.kernel.org/r/20221018191613.4133459-1-Liam.Howlett@oracle.com Link: https://lore.kernel.org/all/Y06yk66SKxlrwwfb@lakrids/ Link: https://lore.kernel.org/all/20201203085350.22624-1-liuzixian4@huawei.com/ Fixes: 4dd1b84140c1 ("mm/mmap: use advanced maple tree API for mmap_region()") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Mark Rutland <mark.rutland@arm.com> Cc: Liu Zixian <liuzixian4@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Makefile
# SPDX-License-Identifier: GPL-2.0
KCSAN_SANITIZE := n
KCOV_INSTRUMENT := n
UBSAN_SANITIZE := n
CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
CFLAGS_core.o := $(call cc-option,-fno-conserve-stack) \
$(call cc-option,-mno-outline-atomics) \
-fno-stack-protector -DDISABLE_BRANCH_PROFILING
obj-y := core.o debugfs.o report.o
KCSAN_INSTRUMENT_BARRIERS_selftest.o := y
obj-$(CONFIG_KCSAN_SELFTEST) += selftest.o
CFLAGS_kcsan_test.o := $(CFLAGS_KCSAN) -g -fno-omit-frame-pointer
obj-$(CONFIG_KCSAN_KUNIT_TEST) += kcsan_test.o
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