log_check / tainted_check failed in ubuntu_boot because of warnings (Found insecure W+X mapping at address) found on F/G/H-riscv

[Po-Hsu Lin]

Issue found on 5.8.0-10-generic riscv

Message reported on boot.

[ 13.483103] ------------[ cut here ]------------
[ 13.483711] riscv/mm: Found insecure W+X mapping at address (____ptrval____)/0xffffffdff8000000
[ 13.484542] WARNING: CPU: 5 PID: 1 at arch/riscv/mm/ptdump.c:200 note_page+0x24c/0x252
[ 13.485175] Modules linked in:
[ 13.485606] CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.8.0-10-generic #12-Ubuntu
[ 13.486091] epc: ffffffe000208f18 ra : ffffffe000208f18 sp : ffffffe1f5bfbb30
[ 13.486471] gp : ffffffe001728ee0 tp : ffffffe1f5bf5080 t0 : ffffffe00173ed88
[ 13.486850] t1 : ffffffe00173ed20 t2 : 00000001fecbe000 s0 : ffffffe1f5bfbb80
[ 13.487250] s1 : ffffffe1f5bfbe10 a0 : 0000000000000053 a1 : 0000000000000020
[ 13.487633] a2 : ffffffe1f5bfb870 a3 : 0000000000000000 a4 : ffffffe0016200f8
[ 13.488040] a5 : ffffffe0016200f8 a6 : 00000000000000b5 a7 : ffffffe0006f2806
[ 13.488421] s2 : ffffffdff8001000 s3 : 0000000000000000 s4 : 0000000000000004
[ 13.488800] s5 : 0000000000000000 s6 : 0000000000000000 s7 : ffffffe1f5bfbd20
[ 13.489322] s8 : ffffffdff8001000 s9 : ffffffe00172a148 s10: ffffffdff8002000
[ 13.489738] s11: ffffffe000c16e20 t3 : 000000000003cec0 t4 : 000000000003cec0
[ 13.490119] t5 : 0000000000000000 t6 : ffffffe001739462
[ 13.490406] status: 0000000000000120 badaddr: 0000000000000000 cause: 0000000000000003
[ 13.490849] ---[ end trace 607c551edff1ef12 ]---

Please find attachment for the boot dmesg log.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1905728

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Francis Ginther (fginther)]

Still seeing this with the 5.8.0-17-generic riscv kernel on groovy. See attached dmesg.

[Thadeu Lima de Souza Cascardo (cascardo)]

This is not a regression and has been this way since the dawn of 5.8 riscv, as we have CONFIG_STRICT_KERNEL_RWX set.

When investigating, I see many fixes that involve the linker script, so I assume this is due to some sections, like init sections carrying both text and data, which could cause this.

I tried picking a lot of commits, and needed to either do extensive backports or carry a lot of commits, and still without success, hitting a linker problem that would require carrying even more fixes.

So, contrary to what has been said about 5.8 bringing up STRICT_KERNEL_RWX to riscv, this is really not ready for prime time, and should be left for future versions.

TL;DR: We should just disable CONFIG_STRICT_KERNEL_RWX on linux-riscv 5.8.

Cascardo.

[Guilherme G. Piccoli (gpiccoli)]

Observed on G/RISC-V , cycle sru-20210510 .

[Guilherme G. Piccoli (gpiccoli)]

Observed on G/RISC-V , cycle sru-20210531 .

[Po-Hsu Lin (cypressyew)]

There is a thread here:
https://<email address hidden>/T/

Looks like this has landed:
https://github.com/torvalds/linux/commit/8a4102a0cf07cc76a18f373f6b49485258cc6af4#diff-2db30a5588193fbb572fc2b96f3b47ae2e7e83351c5122c368b2b6fa56f38cda

And here is another patch from Alex, another fix to 2bfc6cd
("riscv: Move kernel mapping outside of linear mapping") as well.
https://github.com/torvalds/linux/commit/e5c35fa0401971701dcd7675f471b664698244dd#diff-2db30a5588193fbb572fc2b96f3b47ae2e7e83351c5122c368b2b6fa56f38cda

[Brian Murray (brian-murray)]

The Groovy Gorilla has reached end of life, so this bug will not be fixed for that release

[Dimitri John Ledkov (xnox)]

v5.13 in impish-proposed has this fixed on riscv.

it will not be backported to earlier series, hence marking hirsute as wontfix.