From: Pierre Gondois pierre.gondois@arm.com
commit 0e68b5517d3767562889f1d83fdb828c26adb24f upstream.
Running a rt-kernel base on 6.2.0-rc3-rt1 on an Ampere Altra outputs the following: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9, name: kworker/u320:0 preempt_count: 2, expected: 0 RCU nest depth: 0, expected: 0 3 locks held by kworker/u320:0/9: #0: ffff3fff8c27d128 ((wq_completion)efi_rts_wq){+.+.}-{0:0}, at: process_one_work (./include/linux/atomic/atomic-long.h:41) #1: ffff80000861bdd0 ((work_completion)(&efi_rts_work.work)){+.+.}-{0:0}, at: process_one_work (./include/linux/atomic/atomic-long.h:41) #2: ffffdf7e1ed3e460 (efi_rt_lock){+.+.}-{3:3}, at: efi_call_rts (drivers/firmware/efi/runtime-wrappers.c:101) Preemption disabled at: efi_virtmap_load (./arch/arm64/include/asm/mmu_context.h:248) CPU: 0 PID: 9 Comm: kworker/u320:0 Tainted: G W 6.2.0-rc3-rt1 Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 Workqueue: efi_rts_wq efi_call_rts Call trace: dump_backtrace (arch/arm64/kernel/stacktrace.c:158) show_stack (arch/arm64/kernel/stacktrace.c:165) dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) dump_stack (lib/dump_stack.c:114) __might_resched (kernel/sched/core.c:10134) rt_spin_lock (kernel/locking/rtmutex.c:1769 (discriminator 4)) efi_call_rts (drivers/firmware/efi/runtime-wrappers.c:101) [...]
This seems to come from commit ff7a167961d1 ("arm64: efi: Execute runtime services from a dedicated stack") which adds a spinlock. This spinlock is taken through: efi_call_rts() -efi_call_virt() -efi_call_virt_pointer() -arch_efi_call_virt_setup()
Make 'efi_rt_lock' a raw_spinlock to avoid being preempted.
[ardb: The EFI runtime services are called with a different set of translation tables, and are permitted to use the SIMD registers. The context switch code preserves/restores neither, and so EFI calls must be made with preemption disabled, rather than only disabling migration.]
Fixes: ff7a167961d1 ("arm64: efi: Execute runtime services from a dedicated stack") Signed-off-by: Pierre Gondois pierre.gondois@arm.com Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/efi.h | 6 +++--- arch/arm64/kernel/efi.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-)
--- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -33,7 +33,7 @@ int efi_set_mapping_permissions(struct m ({ \ efi_virtmap_load(); \ __efi_fpsimd_begin(); \ - spin_lock(&efi_rt_lock); \ + raw_spin_lock(&efi_rt_lock); \ })
#undef arch_efi_call_virt @@ -42,12 +42,12 @@ int efi_set_mapping_permissions(struct m
#define arch_efi_call_virt_teardown() \ ({ \ - spin_unlock(&efi_rt_lock); \ + raw_spin_unlock(&efi_rt_lock); \ __efi_fpsimd_end(); \ efi_virtmap_unload(); \ })
-extern spinlock_t efi_rt_lock; +extern raw_spinlock_t efi_rt_lock; extern u64 *efi_rt_stack_top; efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
--- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -146,7 +146,7 @@ asmlinkage efi_status_t efi_handle_corru return s; }
-DEFINE_SPINLOCK(efi_rt_lock); +DEFINE_RAW_SPINLOCK(efi_rt_lock);
asmlinkage u64 *efi_rt_stack_top __ro_after_init;