[PATCH] arm64: convert patch_lock to raw lock
From: rostedt@goodmis.org (Steven Rostedt)
Date: 2015-09-30 19:04:36
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On Wed, 30 Sep 2015 11:23:12 -0700 Yang Shi [off-list ref] wrote:
When running kprobe test on arm64 rt kernel, it reports the below warning: root at 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
OK, the above is called from stomp_machine().
[<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.
Yeah, I don't see anything in that lock that can sleep, or should take too much time (it's under stomp_machine). Looks like that should be raw. Acked-by: Steven Rostedt <rostedt@goodmis.org> -- Steve
quoted hunk ↗ jump to hunk
Although the problem is found on rt kernel, the fix should be applicable to mainline kernel too. Signed-off-by: Yang Shi <redacted> --- arch/arm64/kernel/insn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index f341866..c08b9ad 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c@@ -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; }