From: Xianting Tian <xianting.tian@linux.alibaba.com>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, anup@brainfault.org, heiko@sntech.de,
guoren@kernel.org, mick@ics.forth.gr,
alexandre.ghiti@canonical.com
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
crash-utility@redhat.com, huanyi.xj@alibaba-inc.com,
heinrich.schuchardt@canonical.com, k-hagio-ab@nec.com,
hschauhan@nulltrace.org,
Xianting Tian <xianting.tian@linux.alibaba.com>
Subject: [PATCH 1/5] RISC-V: Fixup fast call of crash_kexec()
Date: Sun, 17 Jul 2022 18:13:19 +0800 [thread overview]
Message-ID: <20220717101323.370245-2-xianting.tian@linux.alibaba.com> (raw)
In-Reply-To: <20220717101323.370245-1-xianting.tian@linux.alibaba.com>
Currently, almost all archs (x86, arm64, mips...) support fast call
of crash_kexec() when "regs && kexec_should_crash()" is true. But
RISC-V not, it can only enter crash system via panic(). However panic()
doesn't pass the regs of the real accident scene to crash_kexec(),
it caused we can't get accurate backtrace via gdb,
$ riscv64-linux-gnu-gdb vmlinux vmcore
Reading symbols from vmlinux...
[New LWP 95]
#0 console_unlock () at kernel/printk/printk.c:2557
2557 if (do_cond_resched)
(gdb) bt
#0 console_unlock () at kernel/printk/printk.c:2557
#1 0x0000000000000000 in ?? ()
With the patch we can get the accurate backtrace,
$ riscv64-linux-gnu-gdb vmlinux vmcore
Reading symbols from vmlinux...
[New LWP 95]
#0 0xffffffe00063a4e0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81
81 *(int *)p = 0xdead;
(gdb)
(gdb) bt
#0 0xffffffe00064d5c0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81
#1 0x0000000000000000 in ?? ()
Test code to produce NULL address dereference in test_crash.c,
void *p = NULL;
*(int *)p = 0xdead;
Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
---
arch/riscv/kernel/traps.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index b40426509244..39d0f8bba4b4 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/irq.h>
+#include <linux/kexec.h>
#include <asm/asm-prototypes.h>
#include <asm/bug.h>
@@ -44,6 +45,9 @@ void die(struct pt_regs *regs, const char *str)
ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
+ if (regs && kexec_should_crash(current))
+ crash_kexec(regs);
+
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
--
2.17.1
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next prev parent reply other threads:[~2022-07-17 10:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-17 10:13 [PATCH 0/5] Fixups to work with crash tool Xianting Tian
2022-07-17 10:13 ` Xianting Tian [this message]
2022-07-17 10:13 ` [PATCH 2/5] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian
2022-07-22 7:17 ` Heiko Stübner
2022-07-22 7:43 ` Atish Patra
2022-07-17 10:13 ` [PATCH 3/5] RISC-V: Add arch_crash_save_vmcoreinfo support Xianting Tian
2022-07-17 10:13 ` [PATCH 4/5] riscv: Add modules to virtual kernel memory layout dump Xianting Tian
2022-07-22 7:24 ` Heiko Stübner
2022-07-22 7:51 ` Guo Ren
2022-07-22 10:10 ` Andreas Schwab
2022-07-22 12:49 ` tianxianting
2022-07-17 10:13 ` [PATCH 5/5] RISC-V: Fixup getting correct current pc Xianting Tian
2022-07-22 8:13 ` [Crash-utility] [PATCH 0/5] Fixups to work with crash tool Dave Young
2022-07-24 2:38 ` tianxianting
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