Hi! On 09/03/2021 18:42, Qais Yousef wrote: >>> I tried on 5.12-rc2 and 5.11 but couldn't reproduce the problem using your > I still can't reproduce on 5.12-rc2. > > I do have CONFIG_ARM_MODULE_PLTS=y. Do you need to do something else after > loading the module? I tried starting ftrace, but maybe there's a particular > combination required?
You need to load a BIG module, so big that it has no place in the modules area any more and goes to vmalloc area. >>> instructions on the other email. But most likely because I'm hitting another >>> problem that could be masking it. I'm not sure it is related or just >>> randomly >>> happened to hit it. >>> >>> Did you see something similar? >> [...] >> >>> [ 0.000000] [<c1b01a38>] (ftrace_bug) from [<c046316c>] >>> (ftrace_process_locs+0x2b0/0x518) >>> [ 0.000000] r7:c3817ac4 r6:c38040c0 r5:00000a3c r4:000134e4 >>> [ 0.000000] [<c0462ebc>] (ftrace_process_locs) from [<c2b25240>] >>> (ftrace_init+0xc8/0x174) >>> [ 0.000000] r10:c2ffa000 r9:c2be8a78 r8:c2c5d1fc r7:c2c0c208 >>> r6:00000001 r5:c2d0908c >>> [ 0.000000] r4:c362f518 >>> [ 0.000000] [<c2b25178>] (ftrace_init) from [<c2b00e14>] >>> (start_kernel+0x2f4/0x5b8) >>> [ 0.000000] r9:c2be8a78 r8:dbfffec0 r7:00000000 r6:c36385cc >>> r5:c2d08f00 r4:c2ffa000 >>> [ 0.000000] [<c2b00b20>] (start_kernel) from [<00000000>] (0x0) >> This means, FTRACE has more problems with your kernel/compiler/platform, >> I've addressed similar issue >> in the past, but my patch should be long merged: >> >> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1817963.html >> >> Could it be the same problem as here: >> https://www.spinics.net/lists/arm-kernel/msg854022.html >> >> Seems that the size check deserves something line BUILD_BUG_ON() with >> FTRACE... > So I only see this when I convert all modules to be built-in > > sed -i 's/=m/=y/' .config > > FWIW, I see the problem with your patch applied too. Trying to dig more into > it.. Then it's definitely the problem explained in the second link. If you have THUMB2 kernel, maybe you have to switch to ARM. -- Best regards, Alexander Sverdlin.