From: ShaoBo Huang <huangshaobo6@huawei.com> To: <linux@armlinux.org.uk>, <tixy@linaro.org>, <mhiramat@kernel.org>, <huangshaobo6@huawei.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <gregkh@linuxfoundation.org> Cc: <young.liuyang@huawei.com>, <zengweilin@huawei.com>, <nixiaoming@huawei.com>, <chenzefeng2@huawei.com>, <liucheng32@huawei.com>, <kepler.chenxin@huawei.com>, <xiaoqian9@huawei.com> Subject: [PATCH 4.9.y] arm: kprobes: Allow to handle reentered kprobe on single-stepping Date: Wed, 3 Mar 2021 15:10:52 +0800 [thread overview] Message-ID: <20210303071052.33740-1-huangshaobo6@huawei.com> (raw) From: Masami Hiramatsu <mhiramat@kernel.org> commit f3fbd7ec62dec1528fb8044034e2885f2b257941 upstream This is arm port of commit 6a5022a56ac3 ("kprobes/x86: Allow to handle reentered kprobe on single-stepping") Since the FIQ handlers can interrupt in the single stepping (or preparing the single stepping, do_debug etc.), we should consider a kprobe is hit in the NMI handler. Even in that case, the kprobe is allowed to be reentered as same as the kprobes hit in kprobe handlers (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE). The real issue will happen when a kprobe hit while another reentered kprobe is processing (KPROBE_REENTER), because we already consumed a saved-area for the previous kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jon Medhurst <tixy@linaro.org> Fixes: 24ba613c9d6c ("ARM kprobes: core code") Cc: stable@vger.kernel.org #v2.6.25~v4.11 Signed-off-by: huangshaobo <huangshaobo6@huawei.com> --- arch/arm/probes/kprobes/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 3eb018fa1a1f..c3362ddd6c4c 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -270,6 +270,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs) switch (kcb->kprobe_status) { case KPROBE_HIT_ACTIVE: case KPROBE_HIT_SSDONE: + case KPROBE_HIT_SS: /* A pre- or post-handler probe got us here. */ kprobes_inc_nmissed_count(p); save_previous_kprobe(kcb); @@ -278,6 +279,11 @@ void __kprobes kprobe_handler(struct pt_regs *regs) singlestep(p, regs, kcb); restore_previous_kprobe(kcb); break; + case KPROBE_REENTER: + /* A nested probe was hit in FIQ, it is a BUG */ + pr_warn("Unrecoverable kprobe detected at %p.\n", + p->addr); + /* fall through */ default: /* impossible cases */ BUG(); -- 2.12.3
WARNING: multiple messages have this Message-ID (diff)
From: ShaoBo Huang <huangshaobo6@huawei.com> To: <linux@armlinux.org.uk>, <tixy@linaro.org>, <mhiramat@kernel.org>, <huangshaobo6@huawei.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <gregkh@linuxfoundation.org> Cc: <young.liuyang@huawei.com>, <zengweilin@huawei.com>, <nixiaoming@huawei.com>, <chenzefeng2@huawei.com>, <liucheng32@huawei.com>, <kepler.chenxin@huawei.com>, <xiaoqian9@huawei.com> Subject: [PATCH 4.9.y] arm: kprobes: Allow to handle reentered kprobe on single-stepping Date: Wed, 3 Mar 2021 15:10:52 +0800 [thread overview] Message-ID: <20210303071052.33740-1-huangshaobo6@huawei.com> (raw) From: Masami Hiramatsu <mhiramat@kernel.org> commit f3fbd7ec62dec1528fb8044034e2885f2b257941 upstream This is arm port of commit 6a5022a56ac3 ("kprobes/x86: Allow to handle reentered kprobe on single-stepping") Since the FIQ handlers can interrupt in the single stepping (or preparing the single stepping, do_debug etc.), we should consider a kprobe is hit in the NMI handler. Even in that case, the kprobe is allowed to be reentered as same as the kprobes hit in kprobe handlers (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE). The real issue will happen when a kprobe hit while another reentered kprobe is processing (KPROBE_REENTER), because we already consumed a saved-area for the previous kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jon Medhurst <tixy@linaro.org> Fixes: 24ba613c9d6c ("ARM kprobes: core code") Cc: stable@vger.kernel.org #v2.6.25~v4.11 Signed-off-by: huangshaobo <huangshaobo6@huawei.com> --- arch/arm/probes/kprobes/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 3eb018fa1a1f..c3362ddd6c4c 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -270,6 +270,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs) switch (kcb->kprobe_status) { case KPROBE_HIT_ACTIVE: case KPROBE_HIT_SSDONE: + case KPROBE_HIT_SS: /* A pre- or post-handler probe got us here. */ kprobes_inc_nmissed_count(p); save_previous_kprobe(kcb); @@ -278,6 +279,11 @@ void __kprobes kprobe_handler(struct pt_regs *regs) singlestep(p, regs, kcb); restore_previous_kprobe(kcb); break; + case KPROBE_REENTER: + /* A nested probe was hit in FIQ, it is a BUG */ + pr_warn("Unrecoverable kprobe detected at %p.\n", + p->addr); + /* fall through */ default: /* impossible cases */ BUG(); -- 2.12.3 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-03-03 12:58 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-03 7:10 ShaoBo Huang [this message] 2021-03-03 7:10 ` [PATCH 4.9.y] arm: kprobes: Allow to handle reentered kprobe on single-stepping ShaoBo Huang 2021-03-03 12:18 ` Masami Hiramatsu 2021-03-03 12:18 ` Masami Hiramatsu 2021-03-04 13:28 ` Greg KH 2021-03-04 13:28 ` Greg KH
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