| Message ID | 20220606082308.2883458-1-xianting.tian@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND,v2] RISC-V: Add fast call path of crash_kexec() | expand |
On Mon, 06 Jun 2022 01:23:08 PDT (-0700), xianting.tian@linux.alibaba.com wrote: > 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> > --- > Changes from v1: > - simplify the commit message > --- > 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 fe92e119e6a3..e666ebfa2a64 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); Thanks, this is on for-next.
在 2022/7/22 上午8:11, Palmer Dabbelt 写道: > On Mon, 06 Jun 2022 01:23:08 PDT (-0700), > xianting.tian@linux.alibaba.com wrote: >> 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> >> --- >> Changes from v1: >> - simplify the commit message >> --- >> 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 fe92e119e6a3..e666ebfa2a64 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); > > Thanks, this is on for-next. Palmer, thanks for the reply, Last week, I commit a series of patches(https://lkml.org/lkml/2022/7/17/64 <https://lkml.org/lkml/2022/7/17/64>), which contains this one. This series of patches worked with crash-utility for RISCV64, Could you please review it? We expect 5.19 could support crash-utility, it is a good functionality. crash-utility patches for RISCV64: https://lore.kernel.org/all/20220718025346.411758-1-xianting.tian@linux.alibaba.com/ <https://lore.kernel.org/all/20220718025346.411758-1-xianting.tian@linux.alibaba.com/>
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index fe92e119e6a3..e666ebfa2a64 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);