hi On Tue, Apr 25, 2023 at 6:07 AM Michael Ellerman <mpe@xxxxxxxxxxxxxx> wrote: > > Zhouyi Zhou <zhouzhouyi@xxxxxxxxx> writes: > > Dear PowerPC and RCU developers: > > During the RCU torture test on mainline (on the VM of Opensource Lab > > of Oregon State University), SRCU-P failed with __stack_chk_fail: > ... > > by debugging, I see the r10 is assigned with r13 on c000000000226eb4, > > but if there is a context-switch before c000000000226edc, a false > > positive will be reported. > > > > [1] http://154.220.3.115/logs/0422/configformainline.txt > > Says: > > CONFIG_CC_VERSION_TEXT="powerpc64le-linux-gnu-gcc-10 (Ubuntu 10.4.0-4ubuntu1~22.04) 10.4.0" > > Do you see the same issue with a newer GCC? On PPC vm of Oregon State University (I can grant rsa-pub key ssh access if you are interested), I build and install the gcc from git, then use the newly built gcc to compile the kernel, the bug disappears, I don't know why. Following is what is do: 1) git clone git://gcc.gnu.org/git/gcc.git git rev-parse --short HEAD f0eabc52c9a 2) mkdir gcc/build 3) cd gcc/build 4) ../configure --disable-bootstrap --prefix=/home/ubuntu/gcc-install 5) make -j 4 //my VM has limited memory ;-) 6) make install 7) cd linux-dir git rev-parse --short HEAD 61d325dcbc05 8) export PATH=/home/ubuntu/gcc-install/bin:$PATH 9) make vmlinux -j 8 10) ./whilebash.sh [1] >From the assembly code of srcu_gp_start_if_needed [2], I found stack protector is operated directly on r13: c000000000225098: 30 00 0d e9 ld r8,48(r13) c00000000022509c: 08 00 3c e9 ld r9,8(r28) c0000000002250a0: 14 42 29 7d add r9,r9,r8 c0000000002250a4: ac 04 00 7c hwsync c0000000002250a8: 10 00 7b 3b addi r27,r27,16 c0000000002250ac: 14 da 29 7d add r9,r9,r27 c0000000002250b0: a8 48 00 7d ldarx r8,0,r9 c0000000002250b4: 01 00 08 31 addic r8,r8,1 c0000000002250b8: ad 49 00 7d stdcx. r8,0,r9 c0000000002250bc: f4 ff c2 40 bne- c0000000002250b0 <srcu_gp_start_if_needed+0x220> c0000000002250c0: 28 00 01 e9 ld r8,40(r1) c0000000002250c4: 78 0c 2d e9 ld r9,3192(r13) c0000000002250c8: 79 4a 08 7d xor. r8,r8,r9 c0000000002250cc: 00 00 20 39 li r9,0 c0000000002250d0: 90 03 82 40 bne c000000000225460 <srcu_gp_start_if_needed+0x5d0> console.log is attached at [3]. [1] 140.211.169.189/0425/whilebash.sh [2] http://140.211.169.189/0425/srcu_gp_start_if_needed.txt [3] http://140.211.169.189/0425/console.log I am very glad to cooperate if there is anything else I can do ;-) Cheers Zhouyi > > There's 12.2.0 here: > https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/12.2.0/ > https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/ppc64le/12.2.0/ > > Or if you can build in a Fedora 38 system or container, it has GCC 13. > > cheers
