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charset="utf-8" When booting Xen with CONFIG_USBAN=3Dy and CONFIG_XSM_FLASK=3Dy, UBSAN reports undefined behaviour in avc_dump_av() due to a left shift on a signed int: (XEN) [ 1.104348] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D (XEN) [ 1.105096] UBSAN: Undefined behaviour in xsm/flask/avc.c:184:14 (XEN) [ 1.106052] left shift of 1073741824 by 1 places cannot be represe= nted in type 'int' (XEN) [ 1.107546] Xen WARN at common/ubsan/ubsan.c:176 (XEN) [ 1.108295] ----[ Xen-4.21.1 arm64 debug=3Dy ubsan=3Dy Not tain= ted ]---- (XEN) [ 1.108848] CPU: 0 (XEN) [ 1.109147] PC: 00000a00002f64fc ubsan.c#ubsan_epilogue+0x10/0= xd4 [...] (XEN) [ 1.146320] Xen call trace: (XEN) [ 1.146663] [<00000a00002f64fc>] ubsan.c#ubsan_epilogue+0x10/0x= d4 (PC) (XEN) [ 1.147227] [<00000a00002f7bc4>] __ubsan_handle_shift_out_of_bo= unds+0x1a0/0x290 (LR) (XEN) [ 1.147868] (XEN) [ 1.148177] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D This can be solved by making 'perm' an unsigned 32-bit type (u32). Signed-off-by: Dmytro Prokopchuk --- Test CI pipeline: https://gitlab.com/xen-project/people/dimaprkp4k/xen/-/pipelines/2493649109 --- xen/xsm/flask/avc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/xsm/flask/avc.c b/xen/xsm/flask/avc.c index 3d39e55cae..9c3ffdc070 100644 --- a/xen/xsm/flask/avc.c +++ b/xen/xsm/flask/avc.c @@ -152,7 +152,8 @@ static void __attribute__ ((format (printf, 2, 3))) */ static void avc_dump_av(struct avc_dump_buf *buf, u16 tclass, u32 av) { - int i, i2, perm; + int i, i2; + u32 perm; =20 if ( av =3D=3D 0 ) { --=20 2.43.0