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RISC-V: Add fast call path of crash_kexec()
[ Upstream commit 3f1901110a
]
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;
Reviewed-by: Guo Ren <guoren@kernel.org>
Tested-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220606082308.2883458-1-xianting.tian@linux.alibaba.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
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1 changed files with 4 additions and 0 deletions
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@ -22,6 +22,7 @@
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/irq.h>
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#include <linux/kexec.h>
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#include <asm/processor.h>
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#include <asm/ptrace.h>
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@ -50,6 +51,9 @@ void die(struct pt_regs *regs, const char *str)
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ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV);
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if (regs && kexec_should_crash(current))
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crash_kexec(regs);
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bust_spinlocks(0);
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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spin_unlock_irq(&die_lock);
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