On Thu, 14 Oct 2021 at 16:53, Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
>
> This series adds basic support for parallel relabeling to the libselinux
> API and the setfiles/restorecon CLI tools. It turns out that doing the
> relabeling in parallel can significantly reduce the time even with a
> relatively simple approach.
>
> The first patch is a small cleanup that was found along the way and can
> be applied independently. Patches 2-4 are small incremental changes that
> make the internal selinux_restorecon functions more thread-safe (I kept
> them separate for ease of of review, but maybe they should be rather
> folded into the netx patch...). Patch 5 then completes the parallel
> relabeling implementation at libselinux level and adds a new function
> to the API that allows to make use of it. Finally, patch 6 adds parallel
> relabeling support to he setfiles/restorecon tools.
>
> The relevant man pages are also updated to reflect the new
> functionality.
>
> The patch descriptions contain more details, namely the last patch has
> also some benchmark numbers.
>
> Changes v1->v2:
> - make selinux_log() synchronized instead of introducing selinux_log_sync()
> - fix -Wcomma warning
> - update the swig files as well
> - bump new symbol version to LIBSELINUX_3.3 (this may need further update
> depending on when this gets merged)
>
> Ondrej Mosnacek (6):
> selinux_restorecon: simplify fl_head allocation by using calloc()
> selinux_restorecon: protect file_spec list with a mutex
> libselinux: make selinux_log() thread-safe
> selinux_restorecon: add a global mutex to synchronize progress output
> selinux_restorecon: introduce selinux_restorecon_parallel(3)
> setfiles/restorecon: support parallel relabeling
>
> libselinux/include/selinux/restorecon.h | 14 +
> libselinux/man/man3/selinux_restorecon.3 | 29 ++
> .../man/man3/selinux_restorecon_parallel.3 | 1 +
> libselinux/src/callbacks.c | 8 +-
> libselinux/src/callbacks.h | 13 +-
> libselinux/src/libselinux.map | 5 +
> libselinux/src/selinux_internal.h | 14 +
> libselinux/src/selinux_restorecon.c | 466 ++++++++++++------
> libselinux/src/selinuxswig_python.i | 6 +-
> libselinux/src/selinuxswig_python_exception.i | 8 +
> policycoreutils/setfiles/Makefile | 2 +-
> policycoreutils/setfiles/restore.c | 7 +-
> policycoreutils/setfiles/restore.h | 2 +-
> policycoreutils/setfiles/restorecon.8 | 9 +
> policycoreutils/setfiles/setfiles.8 | 9 +
> policycoreutils/setfiles/setfiles.c | 28 +-
> 16 files changed, 444 insertions(+), 177 deletions(-)
> create mode 100644 libselinux/man/man3/selinux_restorecon_parallel.3
>
> --
> 2.31.1
>
Running under ThreadSanitizer shows multiple instances of the following issue:
==================
WARNING: ThreadSanitizer: data race (pid=16933)
Read of size 4 at 0x7f8790d636f4 by thread T2:
#0 lookup_all ./libselinux/src/label_file.c:954 (libselinux.so.1+0x14d1b)
#1 lookup_common ./libselinux/src/label_file.c:997 (libselinux.so.1+0x14f62)
#2 lookup ./libselinux/src/label_file.c:1095 (libselinux.so.1+0x14fff)
#3 selabel_lookup_common ./libselinux/src/label.c:167
(libselinux.so.1+0x12291)
#4 selabel_lookup_raw ./libselinux/src/label.c:256 (libselinux.so.1+0x126ca)
#5 restorecon_sb ./libselinux/src/selinux_restorecon.c:638
(libselinux.so.1+0x20c76)
#6 selinux_restorecon_thread
./libselinux/src/selinux_restorecon.c:947 (libselinux.so.1+0x21e99)
Previous write of size 4 at 0x7f8790d636f4 by thread T1:
#0 lookup_all ./libselinux/src/label_file.c:954 (libselinux.so.1+0x14d29)
#1 lookup_common ./libselinux/src/label_file.c:997 (libselinux.so.1+0x14f62)
#2 lookup ./libselinux/src/label_file.c:1095 (libselinux.so.1+0x14fff)
#3 selabel_lookup_common ./libselinux/src/label.c:167
(libselinux.so.1+0x12291)
#4 selabel_lookup_raw ./libselinux/src/label.c:256 (libselinux.so.1+0x126ca)
#5 restorecon_sb ./libselinux/src/selinux_restorecon.c:638
(libselinux.so.1+0x20c76)
#6 selinux_restorecon_thread
./libselinux/src/selinux_restorecon.c:947 (libselinux.so.1+0x21e99)
Location is heap block of size 267120 at 0x7f8790d45000 allocated by
main thread:
#0 malloc ../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:655
(libtsan.so.0+0x31799)
#1 sort_specs ./libselinux/src/label_file.h:207 (libselinux.so.1+0x17bd9)
#2 init ./libselinux/src/label_file.c:795 (libselinux.so.1+0x17bd9)
#3 selabel_file_init ./libselinux/src/label_file.c:1293
(libselinux.so.1+0x1835b)
#4 selabel_open ./libselinux/src/label.c:228 (libselinux.so.1+0x125d8)
#5 restore_init ./policycoreutils/setfiles/restore.c:30 (setfiles+0x3886)
#6 main ./policycoreutils/setfiles/setfiles.c:434 (setfiles+0x344e)
Thread T2 (tid=16940, running) created by main thread at:
#0 pthread_create
../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:969
(libtsan.so.0+0x5ad75)
#1 selinux_restorecon_common
./libselinux/src/selinux_restorecon.c:1197 (libselinux.so.1+0x2341c)
#2 selinux_restorecon_parallel
./libselinux/src/selinux_restorecon.c:1306 (libselinux.so.1+0x23985)
#3 process_glob ./policycoreutils/setfiles/restore.c:94 (setfiles+0x3ba4)
#4 main ./policycoreutils/setfiles/setfiles.c:463 (setfiles+0x362a)
Thread T1 (tid=16939, running) created by main thread at:
#0 pthread_create
../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:969
(libtsan.so.0+0x5ad75)
#1 selinux_restorecon_common
./libselinux/src/selinux_restorecon.c:1197 (libselinux.so.1+0x2341c)
#2 selinux_restorecon_parallel
./libselinux/src/selinux_restorecon.c:1306 (libselinux.so.1+0x23985)
#3 process_glob ./policycoreutils/setfiles/restore.c:94 (setfiles+0x3ba4)
#4 main ./policycoreutils/setfiles/setfiles.c:463 (setfiles+0x362a)
SUMMARY: ThreadSanitizer: data race ./libselinux/src/label_file.c:954
in lookup_all
==================
Also some thread joins seems to be missing:
==================
WARNING: ThreadSanitizer: thread leak (pid=16933)
Thread T1 (tid=16939, finished) created by main thread at:
#0 pthread_create
../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:969
(libtsan.so.0+0x5ad75)
#1 selinux_restorecon_common
./libselinux/src/selinux_restorecon.c:1197 (libselinux.so.1+0x2341c)
#2 selinux_restorecon_parallel
./libselinux/src/selinux_restorecon.c:1306 (libselinux.so.1+0x23985)
#3 process_glob ./policycoreutils/setfiles/restore.c:94 (setfiles+0x3ba4)
#4 main ./policycoreutils/setfiles/setfiles.c:463 (setfiles+0x362a)
And 2 more similar thread leaks.
SUMMARY: ThreadSanitizer: thread leak
./libselinux/src/selinux_restorecon.c:1197 in
selinux_restorecon_common
==================
Performance on 4 cores:
real 0m27.323s
user 0m20.824s
sys 0m4.029s
vs
real 0m12.462s
user 0m31.220s
sys 0m4.316s
