On 13 November 2013 12:25, Sandeepa Prabhu <sandeepa.pra...@linaro.org> wrote: >>>> I'm unsure about arm64's debug feature behavior, what does happen when >>>> it performs a single-step on sw-breakpoint? >>>> >>>>> Sandeepa: I think you need to retry Masami's test on the arm64 model, >>>>> since >>>>> I'm fairly sure it won't work as expected without some additional code. >>>> >>>> OK, anyway, for testing same one, we need to port ftrace first. So the next >> >> Sorry for confusion, s/next/fallback is what I meant. Making a kprobe module >> can be done without ftrace port. >> >>>> plan is to make a kprobe module to put a probe (which just printk >>>> something) >>>> on a specific function (e.g. vfs_symlink), and run perf record with >>>> hw-breakpoint as below >>>> >>>> $ perf record -e "mem:0xXXXXXX:k" ln -s /dev/null /tmp/foo >>>> >>>> Note that 0xXXXXXX is the address of vfs_symlink. >>>> >>>> After that, you can see the message in dmesg and also check the perf result >>>> with "sudo perf script --dump" (you can find a PERF_RECORD_SAMPLE entry if >>>> it works) Hi Will, Masami,
I am not sure of 'perf' right now (my minimal rootfs doesn't have) but I tried to test hardware breakpoints using sample modules "samples/hw_breakpoint/" on arm64 upstream branch. This should use same kernel api as perf I believe. 1. Placing watchpoint ( attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R) upon vfs_symlink symbol, but seems watch-point is not triggering at all. 2. Placing text breakpoint (modified sample module with attr.bp_type = HW_BREAKPOINT_X) upon vfs_symlink, and run "ln -s /dev/null /tmp/foo". This time, breakpoint hit but exception is re-cursing infinitely! I have attached the kernel logs for reference. So wanted to check if hw breakpoint/watch-points are working on the upstream branch? Has it been tested recently with sample modules or perf/ptrace? Thanks, Sandeepa
Initializing cgroup subsys cpu Linux version 3.12.0-rc4+ (sandeepa@linaro-workstation) (gcc version 4.7.3 20130328 (prerelease) (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) ) #24 SMP PREEMPT Wed Nov 13 12:04:03 IST 2013 CPU: AArch64 Processor [410fd0f0] revision 0 Machine: RTSM_VE_AEMv8A bootconsole [earlycon0] enabled PERCPU: Embedded 10 pages/cpu @ffffffc87ffa8000 s11776 r8192 d20992 u40960 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1034240 Kernel command line: console=ttyAMA0 root=/dev/mmcblk0p2 earlyprintk=pl011,0x1c090000 consolelog=9 rw PID hash table entries: 4096 (order: 3, 32768 bytes) Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes) Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes) software IO TLB [mem 0x8f8000000-0x8fc000000] (64MB) mapped at [ffffffc878000000-ffffffc87bffffff] Memory: 4058384K/4194304K available (3347K kernel code, 211K rwdata, 1164K rodata, 171K init, 154K bss, 135920K reserved) Virtual kernel memory layout: vmalloc : 0xffffff8000000000 - 0xffffffbbffff0000 (245759 MB) vmemmap : 0xffffffbc01c00000 - 0xffffffbc1f800000 ( 476 MB) modules : 0xffffffbffc000000 - 0xffffffc000000000 ( 64 MB) memory : 0xffffffc000000000 - 0xffffffc880000000 ( 34816 MB) .init : 0xffffffc0004e9000 - 0xffffffc000513e00 ( 172 kB) .text : 0xffffffc000080000 - 0xffffffc0004e8cf4 ( 4516 kB) .data : 0xffffffc000514000 - 0xffffffc000548e80 ( 212 kB) SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1 Preemptible hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4. NR_IRQS:64 nr_irqs:64 0 Architected cp15 timer(s) running at 100.00MHz (phys). Console: colour dummy device 80x25 Calibrating delay loop (skipped), value calculated using timer frequency.. 200.00 BogoMIPS (lpj=1000000) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 256 hw perfevents: enabled with arm/armv8-pmuv3 PMU driver, 9 counters available CPU1: Booted secondary processor CPU2: Booted secondary processor CPU3: Booted secondary processor Brought up 4 CPUs SMP: Total of 4 processors activated. devtmpfs: initialized atomic64 test passed NET: Registered protocol family 16 of_amba_device_create(): amba_device_add() failed (-19) for /smb/motherboard/iofpga@3,00000000/sysctl@020000 vdso: 2 pages (1 code, 1 data) at base ffffffc000519000 hw-breakpoint: found 16 breakpoint and 16 watchpoint registers. Serial: AMBA PL011 UART driver 1c090000.uart: ttyAMA0 at MMIO 0x1c090000 (irq = 37, base_baud = 0) is a PL011 rev2 console [ttyAMA0] enabled, bootconsole disabled console [ttyAMA0] enabled, bootconsole disabled 1c0a0000.uart: ttyAMA1 at MMIO 0x1c0a0000 (irq = 38, base_baud = 0) is a PL011 rev2 1c0b0000.uart: ttyAMA2 at MMIO 0x1c0b0000 (irq = 39, base_baud = 0) is a PL011 rev2 1c0c0000.uart: ttyAMA3 at MMIO 0x1c0c0000 (irq = 40, base_baud = 0) is a PL011 rev2 bio: create slab <bio-0> at 0 SCSI subsystem initialized Switched to clocksource arch_sys_counter NET: Registered protocol family 2 TCP established hash table entries: 32768 (order: 7, 524288 bytes) TCP bind hash table entries: 32768 (order: 7, 524288 bytes) TCP: Hash tables configured (established 32768 bind 32768) TCP: reno registered UDP hash table entries: 2048 (order: 4, 65536 bytes) UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. Unpacking initramfs... Freeing initrd memory: 936K (ffffffc010000000 - ffffffc0100ea000) fuse init (API version 7.22) msgmni has been set to 7928 io scheduler noop registered io scheduler cfq registered (default) Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled smc91x: not found (-19). mousedev: PS/2 mouse device common for all mice TCP: cubic registered NET: Registered protocol family 17 <NUL>Freeing unused kernel memory: 168K (ffffffc0004e9000 - ffffffc000513000) Wed Nov 18 01:00:00 UTC 2009 sh: can't access tty; job control turned off / # / # / # / # / # insm / # insmod [Jkp[J[Jda / # insmod data[J_ / # insmod data_breakpoint.ko [Jf[Jksym=vfs_symlink HW Breakpoint for vfs_symlink write installed / # / # / # / # ln -=s [J[J[Js /de / # ln -s /de[Jv / # ln -s /dev/[Jnull /tmp/a / # / # ln -s /dev/null /tmp/a[J[Jn[Jb / # ls /tm / # ls /tmp/[J [1;36ma[0m [1;36mb[0m [1;34mlog[0m / # / # / # / # / # ls /tmp/[J -al total 0 drwxrwxrwt 3 0 0 100 Nov 18 01:00 [1;34m.[0m drwxrwxr-x 12 1000 1000 0 Nov 18 01:00 [1;34m..[0m lrwxrwxrwx 1 0 0 9 Nov 18 01:00 [1;36ma[0m -> [1;35m/dev/null[0m lrwxrwxrwx 1 0 0 9 Nov 18 01:00 [1;36mb[0m -> [1;35m/dev/null[0m drwxrwxrwx 2 0 0 40 Nov 18 01:00 [1;34mlog[0m / # dmesg Initializing cgroup subsys cpu Linux version 3.12.0-rc4+ (sandeepa@linaro-workstation) (gcc version 4.7.3 20130328 (prerelease) (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) ) #24 SMP PREEMPT Wed Nov 13 12:04:03 IST 2013 CPU: AArch64 Processor [410fd0f0] revision 0 Machine: RTSM_VE_AEMv8A bootconsole [earlycon0] enabled On node 0 totalpages: 1048576 DMA32 zone: 7168 pages used for memmap DMA32 zone: 0 pages reserved DMA32 zone: 524288 pages, LIFO batch:31 Normal zone: 7168 pages used for memmap Normal zone: 524288 pages, LIFO batch:31 PERCPU: Embedded 10 pages/cpu @ffffffc87ffa8000 s11776 r8192 d20992 u40960 pcpu-alloc: s11776 r8192 d20992 u40960 alloc=10*4096 pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1034240 Kernel command line: console=ttyAMA0 root=/dev/mmcblk0p2 earlyprintk=pl011,0x1c090000 consolelog=9 rw PID hash table entries: 4096 (order: 3, 32768 bytes) Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes) Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes) software IO TLB [mem 0x8f8000000-0x8fc000000] (64MB) mapped at [ffffffc878000000-ffffffc87bffffff] Memory: 4058384K/4194304K available (3347K kernel code, 211K rwdata, 1164K rodata, 171K init, 154K bss, 135920K reserved) Virtual kernel memory layout: vmalloc : 0xffffff8000000000 - 0xffffffbbffff0000 (245759 MB) vmemmap : 0xffffffbc01c00000 - 0xffffffbc1f800000 ( 476 MB) modules : 0xffffffbffc000000 - 0xffffffc000000000 ( 64 MB) memory : 0xffffffc000000000 - 0xffffffc880000000 ( 34816 MB) .init : 0xffffffc0004e9000 - 0xffffffc000513e00 ( 172 kB) .text : 0xffffffc000080000 - 0xffffffc0004e8cf4 ( 4516 kB) .data : 0xffffffc000514000 - 0xffffffc000548e80 ( 212 kB) SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1 Preemptible hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4. NR_IRQS:64 nr_irqs:64 0 Architected cp15 timer(s) running at 100.00MHz (phys). Console: colour dummy device 80x25 Calibrating delay loop (skipped), value calculated using timer frequency.. 200.00 BogoMIPS (lpj=1000000) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 256 hw perfevents: enabled with arm/armv8-pmuv3 PMU driver, 9 counters available CPU1: Booted secondary processor CPU2: Booted secondary processor CPU3: Booted secondary processor Brought up 4 CPUs SMP: Total of 4 processors activated. devtmpfs: initialized atomic64 test passed NET: Registered protocol family 16 of_amba_device_create(): amba_device_add() failed (-19) for /smb/motherboard/iofpga@3,00000000/sysctl@020000 vdso: 2 pages (1 code, 1 data) at base ffffffc000519000 hw-breakpoint: found 16 breakpoint and 16 watchpoint registers. Serial: AMBA PL011 UART driver 1c090000.uart: ttyAMA0 at MMIO 0x1c090000 (irq = 37, base_baud = 0) is a PL011 rev2 console [ttyAMA0] enabled, bootconsole disabled 1c0a0000.uart: ttyAMA1 at MMIO 0x1c0a0000 (irq = 38, base_baud = 0) is a PL011 rev2 1c0b0000.uart: ttyAMA2 at MMIO 0x1c0b0000 (irq = 39, base_baud = 0) is a PL011 rev2 1c0c0000.uart: ttyAMA3 at MMIO 0x1c0c0000 (irq = 40, base_baud = 0) is a PL011 rev2 bio: create slab <bio-0> at 0 SCSI subsystem initialized Switched to clocksource arch_sys_counter NET: Registered protocol family 2 TCP established hash table entries: 32768 (order: 7, 524288 bytes) TCP bind hash table entries: 32768 (order: 7, 524288 bytes) TCP: Hash tables configured (established 32768 bind 32768) TCP: reno registered UDP hash table entries: 2048 (order: 4, 65536 bytes) UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. Unpacking initramfs... Freeing initrd memory: 936K (ffffffc010000000 - ffffffc0100ea000) fuse init (API version 7.22) msgmni has been set to 7928 io scheduler noop registered io scheduler cfq registered (default) Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled smc91x: not found (-19). mousedev: PS/2 mouse device common for all mice TCP: cubic registered NET: Registered protocol family 17 Freeing unused kernel memory: 168K (ffffffc0004e9000 - ffffffc000513000) HW Breakpoint for vfs_symlink write installed / # / # / # / # rmm / # rmmod [Jda / # rmmod data[J_ / # rmmod data_breakpoint.ko [J HW Breakpoint for vfs_symlink write uninstalled / # / # / # / # / # insm / # insmod [Jte / # insmod text_breakpoint.ko [Jksym=bfs[J[J[Jvfs_symlink HW Breakpoint for vfs_symlink write installed / # / # / # / # / # / # / # / # / # insmod text_breakpoint.ko ksym=vfs_symlink[J / # rmmod data_breakpoint.ko [J / # dmesg[J / # ls /tmp/ -al[J / # ls /tmp/[J / # ln -s /dev/null /tmp/b[J / # ln -s /dev/null /tmp/a[J[Jc vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 7fd27ce0 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d00 ffffffc0 00159670 ffffffc0 7784ec00 ffffffc8 7f81f180 ffffffc0 7d00: 7fd27d20 ffffffc0 0013e010 ffffffc0 7784ec00 ffffffc8 00000000 00000000 7d20: 7fd27d40 ffffffc0 0013ec5c ffffffc0 00000600 00000000 7f81f180 ffffffc0 7d40: 7fd27d70 ffffffc0 0013ec88 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 7fd27ce0 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d00 ffffffc0 00159670 ffffffc0 7784ec00 ffffffc8 7f81f180 ffffffc0 7d00: 7fd27d20 ffffffc0 0013e010 ffffffc0 7784ec00 ffffffc8 00000000 00000000 7d20: 7fd27d40 ffffffc0 0013ec5c ffffffc0 00000600 00000000 7f81f180 ffffffc0 7d40: 7fd27d70 ffffffc0 0013ec88 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 7fd27ce0 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d00 ffffffc0 00159670 ffffffc0 7784ec00 ffffffc8 7f81f180 ffffffc0 7d00: 7fd27d20 ffffffc0 0013e010 ffffffc0 7784ec00 ffffffc8 00000000 00000000 7d20: 7fd27d40 ffffffc0 0013ec5c ffffffc0 00000600 00000000 7f81f180 ffffffc0 7d40: 7fd27d70 ffffffc0 0013ec88 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 7fd27ce0 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d00 ffffffc0 00159670 ffffffc0 7784ec00 ffffffc8 7f81f180 ffffffc0 7d00: 7fd27d20 ffffffc0 0013e010 ffffffc0 7784ec00 ffffffc8 00000000 00000000 7d20: 7fd27d40 ffffffc0 0013ec5c ffffffc0 00000600 00000000 7f81f180 ffffffc0 7d40: 7fd27d70 ffffffc0 0013ec88 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 00548d84 ffffffc0 00491788 ffffffc0 005132c0 ffffffc0 003bbaa0 ffffffc0 7d20: 7fd27d30 ffffffc0 003bbaac ffffffc0 7fd27e70 ffffffc0 00083630 ffffffc0 7d40: 7784ec00 ffffffc8 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 00548d84 ffffffc0 00491788 ffffffc0 005132c0 ffffffc0 003bbaa0 ffffffc0 7d20: 7fd27d30 ffffffc0 003bbaac ffffffc0 7fd27e70 ffffffc0 00083630 ffffffc0 7d40: 7784ec00 ffffffc8 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 00548d84 ffffffc0 00491788 ffffffc0 005132c0 ffffffc0 003bbaa0 ffffffc0 7d20: 7fd27d30 ffffffc0 003bbaac ffffffc0 7fd27e70 ffffffc0 00083630 ffffffc0 7d40: 7784ec00 ffffffc8 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 00548d84 ffffffc0 00491788 ffffffc0 005132c0 ffffffc0 003bbaa0 ffffffc0 7d20: 7fd27d30 ffffffc0 003bbaac ffffffc0 7fd27e70 ffffffc0 00083630 ffffffc0 7d40: 7784ec00 ffffffc8 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 00548d84 ffffffc0 00491788 ffffffc0 005132c0 ffffffc0 003bbaa0 ffffffc0 7d20: 7fd27d30 ffffffc0 003bbaac ffffffc0 7fd27e70 ffffffc0 00083630 ffffffc0 7d40: 7784ec00 ffffffc8 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 0055b8c0 ffffffc0 00002010 ffffff80 80000145 00000000 003bbaa0 ffffffc0 7d20: 7fd27e70 ffffffc0 000835c0 ffffffc0 7784ec00 ffffffc8 7fd44000 ffffffc0 7d40: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 0055b8c0 ffffffc0 00002010 ffffff80 80000145 00000000 003bbaa0 ffffffc0 7d20: 7fd27e70 ffffffc0 000835c0 ffffffc0 7784ec00 ffffffc8 7fd44000 ffffffc0 7d40: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 0055b8c0 ffffffc0 00002010 ffffff80 80000145 00000000 003bbaa0 ffffffc0 7d20: 7fd27e70 ffffffc0 000835c0 ffffffc0 7784ec00 ffffffc8 7fd44000 ffffffc0 7d40: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 0055b8c0 ffffffc0 00002010 ffffff80 80000145 00000000 003bbaa0 ffffffc0 7d20: 7fd27e70 ffffffc0 000835c0 ffffffc0 7784ec00 ffffffc8 7fd44000 ffffffc0 7d40: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24 Call trace: [<ffffffc00008718c>] dump_backtrace+0x0/0x12c [<ffffffc0000872cc>] show_stack+0x14/0x1c [<ffffffc0003b88e4>] dump_stack+0x70/0xac [<ffffffbffc004020>] $x+0x20/0x34 [text_breakpoint] [<ffffffc0000f8d40>] __perf_event_overflow+0xa4/0x214 [<ffffffc0000f9604>] perf_swevent_overflow+0x50/0x84 [<ffffffc0000f96f4>] perf_swevent_event+0xbc/0xc0 [<ffffffc0000f9938>] perf_bp_event+0x6c/0x78 [<ffffffc00008fd90>] breakpoint_handler+0xec/0x1d8 [<ffffffc0000811ec>] do_debug_exception+0x40/0xac Exception stack(0xffffffc07fd27cb0 to 0xffffffc07fd27dd0) 7ca0: 7784ec00 ffffffc8 7fd44000 ffffffc0 7cc0: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 00512000 ffffffc0 00148400 ffffffc0 7ce0: 7fd27d20 ffffffc0 00081294 ffffffc0 0000200c ffffff80 7fd27d50 ffffffc0 7d00: 0055b8c0 ffffffc0 00002010 ffffff80 80000145 00000000 003bbaa0 ffffffc0 7d20: 7fd27e70 ffffffc0 000835c0 ffffffc0 7784ec00 ffffffc8 7fd44000 ffffffc0 7d40: 7fd27e70 ffffffc0 0013f9d8 ffffffc0 77784048 ffffffc8 7784ec00 ffffffc8 7d60: 7fd44020 ffffffc0 000003ea 00000000 7f81f180 ffffffc0 00556e58 ffffffc0 7d80: 7fd42000 ffffffc0 7fd42000 ffffffc0 00000000 00000000 ffb0c278 00000000 7da0: 00000001 00000000 00000000 00000000 00000000 00000000 ffb0c268 00000000 7dc0: 0007ee24 00000000 00000000 00000000 [<ffffffc0000834ac>] el1_dbg+0x10/0x60 [<ffffffc000143dc4>] SyS_symlink+0x14/0x1c Dump stack from sample_hbp_handler vfs_symlink value is changed CPU: 2 PID: 463 Comm: ln Not tainted 3.12.0-rc4+ #24