Unverified Commit 13d304e4 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!1132 arm64: entry: fix ABBA deadlock when el1_dbg preempts rq->lock context 

Merge Pull Request from: @ci-robot 
 
PR sync from: Yu Liao <liaoyu15@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/6LHNPN45YXYLIR67CAIS2GKF3WWDRBD6/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1132

 

Reviewed-by: default avatarsanglipeng <sanglipeng1@jd.com>
Reviewed-by: default avatarWei Li <liwei391@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents 07d55dca f29e0e1c

arch/arm64/kernel/entry-common.c

+8 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <asm/mmu.h>

#include <asm/sysreg.h>



static DEFINE_PER_CPU(int, dbg_count);

/*

 * This is intended to match the logic in irqentry_enter(), handling the kernel

 * mode transitions only.
@@ -150,10 +151,16 @@ static void noinstr el1_inv(struct pt_regs *regs, unsigned long esr) 
	exit_to_kernel_mode(regs);

}



int in_dbg(void)

{

	return this_cpu_read(dbg_count) > 0;

}



static void noinstr arm64_enter_el1_dbg(struct pt_regs *regs)

{

	regs->lockdep_hardirqs = lockdep_hardirqs_enabled();



	this_cpu_inc(dbg_count);

	lockdep_hardirqs_off(CALLER_ADDR0);

	rcu_nmi_enter();
@@ -172,6 +179,7 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs) 
	rcu_nmi_exit();

	if (restore)

		lockdep_hardirqs_on(CALLER_ADDR0);

	this_cpu_dec(dbg_count);

}



static void noinstr el1_dbg(struct pt_regs *regs, unsigned long esr)

include/linux/preempt.h

+2 −0
Original line number Diff line number Diff line
@@ -352,4 +352,6 @@ static __always_inline void migrate_enable(void) 
	preempt_enable();

}



int in_dbg(void);



#endif /* __LINUX_PREEMPT_H */

kernel/panic.c

+5 −0
Original line number Diff line number Diff line
@@ -761,3 +761,8 @@ static int __init panic_on_taint_setup(char *s) 
	return 0;

}

early_param("panic_on_taint", panic_on_taint_setup);



int __weak in_dbg(void)

{

	return 0;

}

kernel/rcu/tree.c

+1 −1
Original line number Diff line number Diff line
@@ -957,7 +957,7 @@ void __rcu_irq_enter_check_tick(void) 
	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);



	// If we're here from NMI there's nothing to do.

	if (in_nmi())

	if (in_nmi() || in_dbg())

		return;



	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),