https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83356
Bug ID: 83356
Summary: [7 regression] excessive stack usage compiling with
-O2 -fsanitize=bounds -fsanitize=object-size
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: arnd at linaro dot org
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
Created attachment 42826
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42826&action=edit
The AES crypto implementation from linux, preprocessed
After upgrading from gcc-7.1.1 (20170717) to 7.2.1 (20171130), I observed a
warning when building the kernel in configurations with UBSAN:
x86_64-linux-gcc-7.2.1 -Wframe-larger-than=1024 -fsanitize=bounds
-fsanitize=object-size -fno-strict-aliasing -O2 -Wall -c aes_generic.i
/git/arm-soc/crypto/aes_generic.c: In function 'aes_encrypt':
/git/arm-soc/crypto/aes_generic.c:1371:1: warning: the frame size of 3840 bytes
is larger than 1024 bytes [-Wframe-larger-than=]
/git/arm-soc/crypto/aes_generic.c: In function 'aes_decrypt':
/git/arm-soc/crypto/aes_generic.c:1441:1: warning: the frame size of 3840 bytes
is larger than 1024 bytes [-Wframe-larger-than=]
With gcc-7.1.1, the stack frames were 304 bytes each, gcc-8.0.0 uses 512 bytes,
and with "gcc-7.2.1 -Os -fsanitize=bounds -fsanitize=object-size", it's even
smaller at 56 bytes.
I have only noticed this regression with one file in the kernel so far,
crypto/aes_generic.c, all other files apparently stay below the stack frame
warning limit.
