[PATCH] RISC-V: fix taking the text_mutex twice during sifive errata patching

[Geert Uytterhoeven]

Hi Conor,

On Thu, Mar 2, 2023 at 6:45 PM Conor Dooley <conor at kernel.org> wrote:
> From: Conor Dooley <conor.dooley at microchip.com>
>
> Chris pointed out that some bonehead, *cough* me *cough*, added two
> mutex_locks() to the SiFive errata patching. The second was meant to
> have been a mutex_unlock().
>
> Reported-by: Chris Hofstaedtler <zeha at debian.org>
> Fixes: 9493e6f3ce02 ("RISC-V: take text_mutex during alternative patching")
> Signed-off-by: Conor Dooley <conor.dooley at microchip.com>

Thanks for your patch!

This fixes the crash I see (with "earlycon keep_bootcon") on StarLight,
and which I've just bisected to aforementioned commit, so
Tested-by: Geert Uytterhoeven <geert+renesas at glider.be>

You may want to include (a part of) the crash log below in your
patch description, to make it easier for affected people to find
the fix.

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000030
Oops [#1]
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted
6.2.0-rc1-starlight-00079-g9493e6f3ce02 #229
Hardware name: BeagleV Starlight Beta (DT)
epc : __schedule+0x42/0x500
 ra : schedule+0x46/0xce
epc : ffffffff8065957c ra : ffffffff80659a80 sp : ffffffff81203c80
 gp : ffffffff812d50a0 tp : ffffffff8120db40 t0 : ffffffff81203d68
 t1 : 0000000000000001 t2 : 4c45203a76637369 s0 : ffffffff81203cf0
 s1 : ffffffff8120db40 a0 : 0000000000000000 a1 : ffffffff81213958
 a2 : ffffffff81213958 a3 : 0000000000000000 a4 : 0000000000000000
 a5 : ffffffff80a1bd00 a6 : 0000000000000000 a7 : 0000000052464e43
 s2 : ffffffff8120db41 s3 : ffffffff80a1ad00 s4 : 0000000000000000
 s5 : 0000000000000002 s6 : ffffffff81213938 s7 : 0000000000000000
 s8 : 0000000000000000 s9 : 0000000000000001 s10: ffffffff812d7204
 s11: ffffffff80d3c920 t3 : 0000000000000001 t4 : ffffffff812e6dd7
 t5 : ffffffff812e6dd8 t6 : ffffffff81203bb8
status: 0000000200000100 badaddr: 0000000000000030 cause: 000000000000000d
[<ffffffff80659a80>] schedule+0x46/0xce
[<ffffffff80659dce>] schedule_preempt_disabled+0x16/0x28
[<ffffffff8065ae0c>] __mutex_lock.constprop.0+0x3fe/0x652
[<ffffffff8065b138>] __mutex_lock_slowpath+0xe/0x16
[<ffffffff8065b182>] mutex_lock+0x42/0x4c
[<ffffffff8000ad94>] sifive_errata_patch_func+0xf6/0x18c
[<ffffffff80002b92>] _apply_alternatives+0x74/0x76
[<ffffffff80802ee8>] apply_boot_alternatives+0x3c/0xfa
[<ffffffff80803cb0>] setup_arch+0x60c/0x640
[<ffffffff80800926>] start_kernel+0x8e/0x99c
---[ end trace 0000000000000000 ]---

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds