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Commit abffa6f3 authored by Yang Shi's avatar Yang Shi Committed by Will Deacon
Browse files

arm64: convert patch_lock to raw lock 



When running kprobe test on arm64 rt kernel, it reports the below warning:

root@qemu7:~# modprobe kprobe_example
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 484, name: modprobe
CPU: 0 PID: 484 Comm: modprobe Not tainted 4.1.6-rt5 #2
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffffffc0000891b8>] dump_backtrace+0x0/0x128
[<ffffffc000089300>] show_stack+0x20/0x30
[<ffffffc00061dae8>] dump_stack+0x1c/0x28
[<ffffffc0000bbad0>] ___might_sleep+0x120/0x198
[<ffffffc0006223e8>] rt_spin_lock+0x28/0x40
[<ffffffc000622b30>] __aarch64_insn_write+0x28/0x78
[<ffffffc000622e48>] aarch64_insn_patch_text_nosync+0x18/0x48
[<ffffffc000622ee8>] aarch64_insn_patch_text_cb+0x70/0xa0
[<ffffffc000622f40>] aarch64_insn_patch_text_sync+0x28/0x48
[<ffffffc0006236e0>] arch_arm_kprobe+0x38/0x48
[<ffffffc00010e6f4>] arm_kprobe+0x34/0x50
[<ffffffc000110374>] register_kprobe+0x4cc/0x5b8
[<ffffffbffc002038>] kprobe_init+0x38/0x7c [kprobe_example]
[<ffffffc000084240>] do_one_initcall+0x90/0x1b0
[<ffffffc00061c498>] do_init_module+0x6c/0x1cc
[<ffffffc0000fd0c0>] load_module+0x17f8/0x1db0
[<ffffffc0000fd8cc>] SyS_finit_module+0xb4/0xc8

Convert patch_lock to raw loc kto avoid this issue.

Although the problem is found on rt kernel, the fix should be applicable to
mainline kernel too.

Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarYang Shi <yang.shi@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 569ba74a

arch/arm64/kernel/insn.c

+3 −3
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ bool aarch64_insn_is_branch_imm(u32 insn) 
		aarch64_insn_is_bcond(insn));

}



static DEFINE_SPINLOCK(patch_lock);

static DEFINE_RAW_SPINLOCK(patch_lock);



static void __kprobes *patch_map(void *addr, int fixmap)

{
@@ -131,13 +131,13 @@ static int __kprobes __aarch64_insn_write(void *addr, u32 insn) 
	unsigned long flags = 0;

	int ret;



	spin_lock_irqsave(&patch_lock, flags);

	raw_spin_lock_irqsave(&patch_lock, flags);

	waddr = patch_map(addr, FIX_TEXT_POKE0);



	ret = probe_kernel_write(waddr, &insn, AARCH64_INSN_SIZE);



	patch_unmap(FIX_TEXT_POKE0);

	spin_unlock_irqrestore(&patch_lock, flags);

	raw_spin_unlock_irqrestore(&patch_lock, flags);



	return ret;

}