| Message ID | 5733E9E0.1060504@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/11/2016 10:26 PM, Li Bin wrote: > > > on 2016/5/11 23:33, James Morse wrote: >> Hi David, >> >> On 27/04/16 19:52, David Long wrote: >>> From: "David A. Long" <dave.long@linaro.org> >>> >>> This patchset is heavily based on Sandeepa Prabhu's ARM v8 kprobes patches, >>> first seen in October 2013. This version attempts to address concerns raised by >>> reviewers and also fixes problems discovered during testing. >>> >>> This patchset adds support for kernel probes(kprobes), jump probes(jprobes) >>> and return probes(kretprobes) support for ARM64. >>> >>> The kprobes mechanism makes use of software breakpoint and single stepping >>> support available in the ARM v8 kernel. >> >> I applied this series on v4.6-rc7, and built the sample kprobes. They work fine, >> unless I throw ftrace into the mix too. >> >> I enabled the function_graph tracer, then tried to load the jprobe example module: >> -------------------------%<------------------------- >> root@ubuntu:/sys/kernel/debug/tracing# insmod /root/jprobe_example.ko >> Planted jprobe at ffffff80080c8f20, handler addr ffffff8000bb3000 >> root@ubuntu:/sys/kernel/debug/tracing# jprobe: clone_flags = 0x1200011, stack_st >> art = 0x0 stack_size = 0x0 >> Bad mode in Synchronous Abort handler detected, code 0x86000005 -- IABT (current >> EL) >> CPU: 5 PID: 1047 Comm: systemd-udevd Not tainted 4.6.0-rc7+ #4064 >> Hardware name: ARM Juno development board (r1) (DT) >> task: ffffffc975948300 ti: ffffffc974e4c000 task.ti: ffffffc974e4c000 >> PC is at 0x0 >> LR is at 0x0 >> >> pc : [<0000000000000000>] lr : [<0000000000000000>] pstate: 60000145 >> sp : ffffffc974e4ff00 >> x29: 0000000001200011 x28: ffffffc974e4c000 >> x27: ffffff80088d0000 x26: 00000000000000dc >> x25: 0000000000000120 x24: 0000000000000015 >> x23: 0000000060000000 x22: 0000007fa1b40e60 >> x21: 0000007fa1ce70d0 x20: 0000000000000000 >> x19: 0000000000000000 x18: 0000000000000a03 >> x17: 0000007fa1b40d90 x16: ffffff80080c9708 >> x15: 003b9aca00000000 x14: 0000007fddb7e5c0 >> x13: 0000007fa1b40e2c x12: 0000000000d00ff0 >> x11: ffffff8009c4d000 x10: ffffff800920c000 >> x9 : ffffff8008f5c000 x8 : ffffffc976c06800 >> x7 : 000000000006daf2 x6 : 0000000000000015 >> x5 : 0000000000000004 x4 : ffffffc96e8690a0 >> x3 : 0000001ed7cbab74 x2 : ffffffc96e869000 >> x1 : 0000000000000000 x0 : 0000000000000000 >> >> Internal error: Oops - bad mode: 0 [#1] PREEMPT SMP >> Modules linked in: jprobe_example >> CPU: 5 PID: 1047 Comm: systemd-udevd Not tainted 4.6.0-rc7+ #4064 >> Hardware name: ARM Juno development board (r1) (DT) >> task: ffffffc975948300 ti: ffffffc974e4c000 task.ti: ffffffc974e4c000 >> PC is at 0x0 >> LR is at 0x0 >> >> pc : [<0000000000000000>] lr : [<0000000000000000>] pstate: 60000145 >> sp : ffffffc974e4ff00 >> x29: 0000000001200011 x28: ffffffc974e4c000 >> x27: ffffff80088d0000 x26: 00000000000000dc >> x25: 0000000000000120 x24: 0000000000000015 >> x23: 0000000060000000 x22: 0000007fa1b40e60 >> x21: 0000007fa1ce70d0 x20: 0000000000000000 >> x19: 0000000000000000 x18: 0000000000000a03 >> x17: 0000007fa1b40d90 x16: ffffff80080c9708 >> x15: 003b9aca00000000 x14: 0000007fddb7e5c0 >> x13: 0000007fa1b40e2c x12: 0000000000d00ff0 >> x11: ffffff8009c4d000 x10: ffffff800920c000 >> x9 : ffffff8008f5c000 x8 : ffffffc976c06800 >> x7 : 000000000006daf2 x6 : 0000000000000015 >> x5 : 0000000000000004 x4 : ffffffc96e8690a0 >> x3 : 0000001ed7cbab74 x2 : ffffffc96e869000 >> x1 : 0000000000000000 x0 : 0000000000000000 >> >> Process systemd-udevd (pid: 1047, stack limit = 0xffffffc974e4c020) >> Stack: (0xffffffc974e4ff00 to 0xffffffc974e50000) >> ff00: 0000000000000417 0000007fa1ce76f0 00000000000000dc 0000000000000417 >> ff20: 00000000ffffffff 0000007fddb7ecf8 0000000000000005 ffffffffffffffff >> ff40: 00000000ff000001 003b9aca00000000 000000555b3868b0 0000007fa1b40d90 >> ff60: 0000000000000a03 0000007fddb7e5c0 0000000000000000 0000007fddb7e5e0 >> ff80: 000000555b358000 000000558f56f0e0 0000000000000000 000000558f574f00 >> ffa0: 000000558f574f00 00000000000004fa 000000558f56f010 0000007fddb7e600 >> ffc0: 0000007fa1b40e2c 0000007fddb7e5c0 0000007fa1b40e60 0000000060000000 >> ffe0: 0000000001200011 00000000000000dc 0004000084000200 0800000002000000 >> Call trace: >> [< (null)>] (null) >> Code: bad PC value >> ---[ end trace 35d24aad799c2941 ]--- >> -------------------------%<------------------------- >> > > To solve this, it should pause function tracing before the jprobe handler is called > and unpause it before it returns back to the function it probed. > > diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c > index db2d95c..b21ed00 100644 > --- a/arch/arm64/kernel/kprobes.c > +++ b/arch/arm64/kernel/kprobes.c > @@ -714,6 +714,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) > > instruction_pointer_set(regs, (long)jp->entry); > preempt_disable(); > + pause_graph_tracing(); > return 1; > } > > @@ -757,6 +758,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) > show_regs(regs); > BUG(); > } > + unpause_graph_tracing(); > *regs = kcb->jprobe_saved_regs; > memcpy((void *)stack_addr, kcb->jprobes_stack, > MIN_STACK_SIZE(stack_addr)); > > > Li Bin > >> >> Thanks, >> >> >> James Thanks for the suggested fix. -dl
On Thu, May 12, 2016 at 10:26:40AM +0800, Li Bin wrote: > > > on 2016/5/11 23:33, James Morse wrote: > > Hi David, > > > > On 27/04/16 19:52, David Long wrote: > >> From: "David A. Long" <dave.long@linaro.org> > >> > >> This patchset is heavily based on Sandeepa Prabhu's ARM v8 kprobes patches, > >> first seen in October 2013. This version attempts to address concerns raised by > >> reviewers and also fixes problems discovered during testing. > >> > >> This patchset adds support for kernel probes(kprobes), jump probes(jprobes) > >> and return probes(kretprobes) support for ARM64. > >> > >> The kprobes mechanism makes use of software breakpoint and single stepping > >> support available in the ARM v8 kernel. > > > > I applied this series on v4.6-rc7, and built the sample kprobes. They work fine, > > unless I throw ftrace into the mix too. > > > > I enabled the function_graph tracer, then tried to load the jprobe example module: > > -------------------------%<------------------------- > > root@ubuntu:/sys/kernel/debug/tracing# insmod /root/jprobe_example.ko > > Planted jprobe at ffffff80080c8f20, handler addr ffffff8000bb3000 > > root@ubuntu:/sys/kernel/debug/tracing# jprobe: clone_flags = 0x1200011, stack_st > > art = 0x0 stack_size = 0x0 > > Bad mode in Synchronous Abort handler detected, code 0x86000005 -- IABT (current > > EL) > > CPU: 5 PID: 1047 Comm: systemd-udevd Not tainted 4.6.0-rc7+ #4064 > > Hardware name: ARM Juno development board (r1) (DT) > > task: ffffffc975948300 ti: ffffffc974e4c000 task.ti: ffffffc974e4c000 > > PC is at 0x0 > > LR is at 0x0 > > > > pc : [<0000000000000000>] lr : [<0000000000000000>] pstate: 60000145 > > sp : ffffffc974e4ff00 > > x29: 0000000001200011 x28: ffffffc974e4c000 > > x27: ffffff80088d0000 x26: 00000000000000dc > > x25: 0000000000000120 x24: 0000000000000015 > > x23: 0000000060000000 x22: 0000007fa1b40e60 > > x21: 0000007fa1ce70d0 x20: 0000000000000000 > > x19: 0000000000000000 x18: 0000000000000a03 > > x17: 0000007fa1b40d90 x16: ffffff80080c9708 > > x15: 003b9aca00000000 x14: 0000007fddb7e5c0 > > x13: 0000007fa1b40e2c x12: 0000000000d00ff0 > > x11: ffffff8009c4d000 x10: ffffff800920c000 > > x9 : ffffff8008f5c000 x8 : ffffffc976c06800 > > x7 : 000000000006daf2 x6 : 0000000000000015 > > x5 : 0000000000000004 x4 : ffffffc96e8690a0 > > x3 : 0000001ed7cbab74 x2 : ffffffc96e869000 > > x1 : 0000000000000000 x0 : 0000000000000000 > > > > Internal error: Oops - bad mode: 0 [#1] PREEMPT SMP > > Modules linked in: jprobe_example > > CPU: 5 PID: 1047 Comm: systemd-udevd Not tainted 4.6.0-rc7+ #4064 > > Hardware name: ARM Juno development board (r1) (DT) > > task: ffffffc975948300 ti: ffffffc974e4c000 task.ti: ffffffc974e4c000 > > PC is at 0x0 > > LR is at 0x0 > > > > pc : [<0000000000000000>] lr : [<0000000000000000>] pstate: 60000145 > > sp : ffffffc974e4ff00 > > x29: 0000000001200011 x28: ffffffc974e4c000 > > x27: ffffff80088d0000 x26: 00000000000000dc > > x25: 0000000000000120 x24: 0000000000000015 > > x23: 0000000060000000 x22: 0000007fa1b40e60 > > x21: 0000007fa1ce70d0 x20: 0000000000000000 > > x19: 0000000000000000 x18: 0000000000000a03 > > x17: 0000007fa1b40d90 x16: ffffff80080c9708 > > x15: 003b9aca00000000 x14: 0000007fddb7e5c0 > > x13: 0000007fa1b40e2c x12: 0000000000d00ff0 > > x11: ffffff8009c4d000 x10: ffffff800920c000 > > x9 : ffffff8008f5c000 x8 : ffffffc976c06800 > > x7 : 000000000006daf2 x6 : 0000000000000015 > > x5 : 0000000000000004 x4 : ffffffc96e8690a0 > > x3 : 0000001ed7cbab74 x2 : ffffffc96e869000 > > x1 : 0000000000000000 x0 : 0000000000000000 > > > > Process systemd-udevd (pid: 1047, stack limit = 0xffffffc974e4c020) > > Stack: (0xffffffc974e4ff00 to 0xffffffc974e50000) > > ff00: 0000000000000417 0000007fa1ce76f0 00000000000000dc 0000000000000417 > > ff20: 00000000ffffffff 0000007fddb7ecf8 0000000000000005 ffffffffffffffff > > ff40: 00000000ff000001 003b9aca00000000 000000555b3868b0 0000007fa1b40d90 > > ff60: 0000000000000a03 0000007fddb7e5c0 0000000000000000 0000007fddb7e5e0 > > ff80: 000000555b358000 000000558f56f0e0 0000000000000000 000000558f574f00 > > ffa0: 000000558f574f00 00000000000004fa 000000558f56f010 0000007fddb7e600 > > ffc0: 0000007fa1b40e2c 0000007fddb7e5c0 0000007fa1b40e60 0000000060000000 > > ffe0: 0000000001200011 00000000000000dc 0004000084000200 0800000002000000 > > Call trace: > > [< (null)>] (null) > > Code: bad PC value > > ---[ end trace 35d24aad799c2941 ]--- > > -------------------------%<------------------------- > > > > To solve this, it should pause function tracing before the jprobe handler is called > and unpause it before it returns back to the function it probed. > > diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c > index db2d95c..b21ed00 100644 > --- a/arch/arm64/kernel/kprobes.c > +++ b/arch/arm64/kernel/kprobes.c > @@ -714,6 +714,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) > > instruction_pointer_set(regs, (long)jp->entry); > preempt_disable(); > + pause_graph_tracing(); > return 1; > } > > @@ -757,6 +758,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) > show_regs(regs); > BUG(); > } > + unpause_graph_tracing(); > *regs = kcb->jprobe_saved_regs; > memcpy((void *)stack_addr, kcb->jprobes_stack, > MIN_STACK_SIZE(stack_addr)); > > I tested this fix, it works. thanks Huang Shijie
diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c index db2d95c..b21ed00 100644 --- a/arch/arm64/kernel/kprobes.c +++ b/arch/arm64/kernel/kprobes.c @@ -714,6 +714,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) instruction_pointer_set(regs, (long)jp->entry); preempt_disable(); + pause_graph_tracing(); return 1; } @@ -757,6 +758,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) show_regs(regs); BUG(); } + unpause_graph_tracing(); *regs = kcb->jprobe_saved_regs; memcpy((void *)stack_addr, kcb->jprobes_stack, MIN_STACK_SIZE(stack_addr));