From: Conor Dooley conor.dooley@microchip.com
commit bf89b7ee52af5a5944fa3539e86089f72475055b upstream.
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().
This results in errors such as
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 ]---
Reported-by: Chris Hofstaedtler zeha@debian.org Fixes: 9493e6f3ce02 ("RISC-V: take text_mutex during alternative patching") Signed-off-by: Conor Dooley conor.dooley@microchip.com Tested-by: Geert Uytterhoeven geert+renesas@glider.be Link: https://lore.kernel.org/r/20230302174154.970746-1-conor@kernel.org [Palmer: pick up Geert's bug report from the thread] Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/errata/sifive/errata.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c index 5b77d7310e391..c24a349dd026d 100644 --- a/arch/riscv/errata/sifive/errata.c +++ b/arch/riscv/errata/sifive/errata.c @@ -110,7 +110,7 @@ void __init_or_module sifive_errata_patch_func(struct alt_entry *begin, if (cpu_req_errata & tmp) { mutex_lock(&text_mutex); patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); - mutex_lock(&text_mutex); + mutex_unlock(&text_mutex); cpu_apply_errata |= tmp; } }