linux/tools/testing/radix-tree/Makefile
Matthew Wilcox (Oracle) 7e934cf5ac xarray: Fix early termination of xas_for_each_marked
xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:

TASK1                                   TASK2
page_cache_delete()         	        find_get_pages_range_tag()
                                          xas_for_each_marked()
                                            xas_find_marked()
                                              off = xas_find_chunk()

  xas_store(&xas, NULL)
    xas_init_marks(&xas);
    ...
    rcu_assign_pointer(*slot, NULL);
                                              entry = xa_entry(off);

And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).

If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).

Reported-by: Jan Kara <jack@suse.cz>
CC: stable@vger.kernel.org
Fixes: ef8e5717db ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-03-12 17:42:08 -04:00

58 lines
1.5 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
CFLAGS += -I. -I../../include -g -Og -Wall -D_LGPL_SOURCE -fsanitize=address \
-fsanitize=undefined
LDFLAGS += -fsanitize=address -fsanitize=undefined
LDLIBS+= -lpthread -lurcu
TARGETS = main idr-test multiorder xarray
CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o bitmap.o
OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \
regression4.o tag_check.o multiorder.o idr-test.o iteration_check.o \
iteration_check_2.o benchmark.o
ifndef SHIFT
SHIFT=3
endif
ifeq ($(BUILD), 32)
CFLAGS += -m32
LDFLAGS += -m32
endif
targets: generated/map-shift.h $(TARGETS)
main: $(OFILES)
idr-test.o: ../../../lib/test_ida.c
idr-test: idr-test.o $(CORE_OFILES)
xarray: $(CORE_OFILES)
multiorder: multiorder.o $(CORE_OFILES)
clean:
$(RM) $(TARGETS) *.o radix-tree.c idr.c generated/map-shift.h
vpath %.c ../../lib
$(OFILES): Makefile *.h */*.h generated/map-shift.h \
../../include/linux/*.h \
../../include/asm/*.h \
../../../include/linux/xarray.h \
../../../include/linux/radix-tree.h \
../../../include/linux/idr.h
radix-tree.c: ../../../lib/radix-tree.c
sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@
idr.c: ../../../lib/idr.c
sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@
xarray.o: ../../../lib/xarray.c ../../../lib/test_xarray.c
generated/map-shift.h:
@if ! grep -qws $(SHIFT) generated/map-shift.h; then \
echo "#define XA_CHUNK_SHIFT $(SHIFT)" > \
generated/map-shift.h; \
fi