[PATCH v3] ARC: prevent showing irrelevant exception info in signal message
We process signals in the end of syscall/exception handler. It the signal is fatal we print register's content using show_regs function. show_regs() also prints information about last exception happened. In case of multicore system we can catch the situation when we will print wrong information about exception. See the example: __ CPU-0: started to handle page fault CPU-1: sent signal to process, which is executed on CPU-0 CPU-0: ended page fault handle. Started to process signal before returnig to userspace. Process signal, which is send from CPU-0. As th signal is fatal we call show_regs(). show_regs() will show information about last exception which is *page fault* (instead of "trap" which is used for signals and happened on CPU-0) So we will get message like this: # ./waitpid02 potentially unexpected fatal signal 8. Path: /home/waitpid02 CPU: 0 PID: 100 Comm: waitpid02 Not tainted 4.10.0-rc4 #2 task: 9f11c200 task.stack: 9f3ae000 [ECR ]: 0x00050200 => Invalid Write @ 0x by insn @ 0x000123ec [EFA ]: 0x [BLINK ]: 0x123ea [ERET ]: 0x123ec @off 0x123ec in [/home/waitpid02] VMA: 0x0001 to 0x00016000 [STAT32]: 0x80080882 : IE U BTA: 0x000123ea SP: 0x5ffd3db0 FP: 0x LPS: 0x20031684 LPE: 0x2003169a LPC: 0x0006 [-other-info-] This message is confusing because it show information about page fault ( [ECR ]: 0x00050200 => Invalid Write ) which is absolutely irrelevant to signal. This situation was reproduced with waitpid02 LTP test. _ So remove printing information about exceptions from show_regs() to avoid confusing messages. Print information about exceptions only in required places instead of show_regs() Now we don't print information about exceptions if signal is simply send by another userspace app. So in case of waitpid02 we will print next message: _ # ./waitpid02 potentially unexpected fatal signal 8. Path: /root/waitpid02 CPU: 2 PID: 105 Comm: waitpid02 Not tainted 4.18.0-rc8-2-gde0f6d6aeb53-dirty #17 [ECR ]: 0x00050100 [EFA ]: 0x [BLINK ]: 0x20001486 [-other-info-] _ This patch fix STAR 9001146055: waitpid02: Invalid Write @ 0x by insn @ 0x000123ec NOTE: To be more clear I give examples of different faults (signal-based, userspace/kernelspace exception-based) with different values of "/proc/sys/kernel/print-fatal-signals" option. 0) NULL pointer access from user space, print-fatal-signals == 1: >8--- # ./arc_hell Exception: arc_hell[103]: at 0x2003a35c [off 0x2e35c in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] ECR: 0x00050100 => Invalid Read @ 0x by insn @ 0x2003a35c potentially unexpected fatal signal 11. Path: /root/arc_hell CPU: 1 PID: 103 Comm: arc_hell Not tainted 4.18.0-rc8-2-gde0f6d6aeb53-dirty #17 [ECR ]: 0x00050100 [EFA ]: 0x [BLINK ]: 0x20039ef8 [ERET ]: 0x2003a35c [STAT32]: 0x80080882 : IE U BTA: 0x2003a358 SP: 0x5fa27dc4 FP: 0x5fa27de8 LPS: 0x2003a628 LPE: 0x2003a62c LPC: 0x r00: 0x r01: 0x200740b0 r02: 0x0001 r03: 0x0007 r04: 0x80808080 r05: 0x2f2f2f2f r06: 0x7c7a2f43 r07: 0x r08: 0x1a131100 r09: 0x2008b1e0 r10: 0x20003a5c r11: 0x20004038 r12: 0x20039ef8 r13: 0x200740b0 r14: 0x r15: 0x200740b0 r16: 0x r17: 0x0007d468 r18: 0x0009313a r19: 0x r20: 0x0009c22c r21: 0x0009c23c r22: 0x0009ab64 r23: 0x r24: 0x0009dfc5 r25: 0x20004b70 Segmentation fault >8--- 1) NULL pointer access from user space, print-fatal-signals == 0: >8--- # ./arc_hell Exception: arc_hell[107]: at 0x2003a35c [off 0x2e35c in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] ECR: 0x00050100 => Invalid Read @ 0x by insn @ 0x2003a35c Segmentation fault >8--- 2) Process killed by signal (waitpid02 test), print-fatal-signals == 1: >8--- # ./waitpid02 potentially unexpected fatal signal 8. Path: /root/waitpid02 CPU: 2 PID: 105 Comm: waitpid02 Not tainted 4.18.0-rc8-2-gde0f6d6aeb53-dirty #17 [ECR ]: 0x00050100 [EFA ]: 0x [BLINK ]: 0x20001486 [ERET ]: 0x2000146c [STAT32]: 0x80080082 : IE U BTA: 0x2fc4 SP: 0x5fa21d64 FP: 0x LPS: 0x200524a0 LPE: 0x200524b6 LPC: 0x0006 r00: 0x2000c0dc r01: 0x0018 r02: 0x0001159a r03: 0x0001 r04: 0x r05: 0x0045 r06: 0x004e r07: 0x01010101 r08: 0x00dc r09: 0x200a31e0 r10: 0x20003a5c r11: 0x20004038 r12: 0x20001486 r13: 0x20004174 r14: 0x07ca2bc0 r15: 0x20004078 r16: 0x r17: 0x20004038 r18: 0x0001 r19: 0x r20: 0x0001159a r21: 0x0001 r22: 0x r23: 0x0004 r24: 0x2000d1fc r25: 0x20004cd0 >8--- 3) Process killed by signal (waitpid02 test), print-fatal-signals == 0:
[RFC] ARC: ARCv2: Introduce SmaRT support
Add compile-time 'ARC_USE_SMART' option for enabling SmaRT support. Small real time trace (SmaRT) is an optional on-chip debug hardware component that captures instruction-trace history. It stores the address of the most recent non-sequential instructions executed into internal buffer. Usually we use MetaWare debugger to enable SmaRT and display trace information. This patch allows to display the decoded content of SmaRT buffer without MetaWare debugger. It is done by extending ordinary exception message with decoded SmaRT instruction-trace history. In some cases it's really usefull as it allows to show pre-exception instruction-trace which was not tainted by exception handler code, printk code, etc... Nevertheless this option has negative performance impact due to implementation as we dump SmaRT buffer content into external memory buffer in the begining of every slowpath exception handler code. We choose this implementation as a compromise between performance impact and SmaRT buffer tainting. Although the performance impact is not really significant (according to lmbench) we leave this option disabled by default. Here is th examples of user-space and kernel-space fault messages with 'ARC_USE_SMART' option enabled: User-space exception: --->8- Exception: u_hell[99]: at 0x103a2 [off 0x103a2 in /root/u_hell, VMA: 0001:00012000] ECR: 0x00050200 => Invalid Write @ 0x by insn @ 0x000103a2 SmaRT (64 entries): [ 0]V 0x90232358 -> 0x9022ce3c [src do_page_fault+0x2c/0x2d8] [dst populate_smart+0x0/0x9c] [ 1]V 0x9022e3f8 -> 0x9023232c [src EV_TLBProtV+0xec/0xf0] [dst do_page_fault+0x0/0x2d8] [ 2]V 0x90233194 -> 0x9022e30c [src do_slow_path_pf+0x10/0x14] [dst EV_TLBProtV+0x0/0xf0] [ 3]V 0x90233120 -> 0x90233184 [src EV_TLBMissD+0x80/0xe0] [dst do_slow_path_pf+0x0/0x14] [ 4] E V 0x000103a2 -> 0x902330a0 [off 0x103a2 in /root/u_hell, VMA: 0001:00012000] [dst EV_TLBMissD+0x0/0xe0] [ 5] U V 0x2004f238 -> 0x00010398 [off 0x43238 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x10398 in /root/u_hell, VMA: 0001:00012000] [ 6] U V 0x20049a82 -> 0x2004f214 [off 0x3da82 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x43214 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [ 7] U V 0x20049a64 -> 0x20049a76 [off 0x3da64 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x3da76 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [ 8] U V 0x2001d8e4 -> 0x20049a58 [off 0x118e4 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x3da58 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [ 9] U V 0x2001d8f4 -> 0x2001d8a8 [off 0x118f4 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x118a8 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [ 10] U V 0x2001d5c8 -> 0x2001d8f0 [off 0x115c8 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] [off 0x118f0 in /lib/libuClibc-1.0.18.so, VMA: 2000c000:20072000] ...[snip]... --->8- Kernel-space exception: --->8- Exception: at dw_mci_probe+0xf0/0x944: ECR: 0x00050100 => Invalid Read @ 0x by insn @ 0x905e26e0 SmaRT (64 entries): [ 0]V 0x90232358 -> 0x9022ce3c [src do_page_fault+0x2c/0x2d8] [dst populate_smart+0x0/0x9c] [ 1]V 0x9022e3f8 -> 0x9023232c [src EV_TLBProtV+0xec/0xf0] [dst do_page_fault+0x0/0x2d8] [ 2]V 0x9022e398 -> 0x9022e3a0 [src EV_TLBProtV+0x8c/0xf0] [dst EV_TLBProtV+0x94/0xf0] [ 3]V 0x90233194 -> 0x9022e30c [src do_slow_path_pf+0x10/0x14] [dst EV_TLBProtV+0x0/0xf0] [ 4]V 0x902330dc -> 0x90233184 [src EV_TLBMissD+0x3c/0xe0] [dst do_slow_path_pf+0x0/0x14] [ 5] E V 0x905e26e0 -> 0x902330a0 [src dw_mci_probe+0xf0/0x944] [dst EV_TLBMissD+0x0/0xe0] [ 6]V 0x904cb940 -> 0x905e26d6 [src clk_get_rate+0xdc/0x208] [dst dw_mci_probe+0xe6/0x944] [ 7]V 0x9074e14a -> 0x904cb932 [src mutex_unlock+0x1e/0x24] [dst clk_get_rate+0xce/0x208] [ 8]V 0x904cb92e -> 0x9074e12c [src clk_get_rate+0xca/0x208] [dst mutex_unlock+0x0/0x24] [ 9]V 0x904cb8ea -> 0x904cb91e [src clk_get_rate+0x86/0x208] [dst clk_get_rate+0xba/0x208] [ 10]V 0x904cb8c2 -> 0x904cb8d0 [src clk_get_rate+0x5e/0x208] [dst clk_get_rate+0x6c/0x208] [ 11]V 0x9074e01a -> 0x904cb884 [src mutex_trylock+0x4e/0x50] [dst clk_get_rate+0x20/0x208] [ 12]V 0x9074e00e -> 0x9074e018 [src mutex_trylock+0x42/0x50] [dst mutex_trylock+0x4c/0x50] [ 13]V 0x9074dfdc -> 0x9074dff0 [src mutex_trylock+0x10/0x50] [dst mutex_trylock+0x24/0x50] [ 14]V 0x904cb880 -> 0x9074dfcc [src clk_get_rate+0x1c/0x208] [dst mutex_trylock+0x0/0x50] [ 15]V 0x905e26d2 -> 0x904cb864 [src dw_mci_probe+0xe2/0x944] [dst clk_get_rate+0x0/0x208] ...[snip]... --->8- TODO: Add runtime procfs options to configure/suspend SmaRT. Add SmaR
kisskb: OK linus/axs103_smp_defconfig/arcv2 Sat Oct 20, 03:02
OK linus/axs103_smp_defconfig/arcv2 Sat Oct 20, 03:02
http://kisskb.ellerman.id.au/kisskb/buildresult/13556494/
Commit: Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc
2a96661054452c3016c377d72a38c6d4948ea6ae
Compiler: arc-linux-gcc.br_real (Buildroot 2016.11-git-00613-ge98b4dd) 6.2.1
20160824
Possible errors
---
#define KERN_ERR KERN_SOH "3" /* error conditions */
#define KERN_ERR KERN_SOH "3" /* error conditions */
#define KERN_ERR KERN_SOH "3" /* error conditions */
Possible warnings (79)
--
kernel/dma/direct.c:46:5: warning: format '%zu' expects argument of type
'size_t', but argument 5 has type 'unsigned int' [-Wformat=]
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
fs/ext4/inode.c:3622:12: warning: format '%zd' expects argument of type 'signed
size_t', but argument 6 has type 'ssize_t {aka int}' [-Wformat=]
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
fs/ext4/page-io.c:163:5: warning: format '%zd' expects argument of type 'signed
size_t', but argument 6 has type 'ssize_t {aka int}' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 2 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 2 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1382:17: warning: format '%zu' expects argument of type 'size_t',
but argument 4 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1382:17: warning: format '%zu' expects argument of type 'size_t',
but argument 5 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 2 has type 'unsigned int' [-Wformat=]
#define KERN_WARNING KERN_SOH "4" /* warning conditions */
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 3 has type 'unsigned int' [-Wformat=]
#define KERN_WARNING KERN_SOH "4" /* warning conditions */
mm/percpu.c:1948:27: warning: format '%zu' expects argument of type 'size_t',
but argument 3 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1948:32: warning: format '%zu' expects argument of type 'size_t',
but argument 4 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1948:37: warning: format '%zu' expects argument of type 'size_t',
but argument 5 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1948:42: warning: format '%zu' expects argument of type 'size_t',
but argument 6 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1948:52: warning: format '%zu' expects argument of type 'size_t',
but argument 7 has type 'unsigned int' [-Wformat=]
mm/percpu.c:1948:56: warning: format '%zu' expects argument of type 'size_t',
but argument 8 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 2 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 4 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 5 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 6 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of
type 'size_t', but argument 7 has type 'unsigned int' [-Wformat=]
drivers/base/regmap/regmap.c:1507:22: warning: format '%zu' expects argument of
type 'size_t', but argument 5 has type 'unsigned int' [-Wformat=]
drivers/base/component.c:174:24: warning: format '%zu' expects argument of type
'size_t', but argument 4 has type 'unsigned int' [-Wformat=]
fs/ext4/xattr.c:482:8: warning: format '%zu' expects argument of type 'size_t',
but argument 6 has type 'unsigned int' [-Wformat=]
include/linux/kern_levels.h:5:18: warning: format '%zd' expects argument of
type 'signed size_t', but argument 3 has type 'size_t {aka unsigned int}'
[-Wformat=]
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distinct pointer types
lacks a cast
include/linux/kernel.h:845:29: warning: comparison of distin
kisskb: OK linus/axs101_defconfig/arcompact Sat Oct 20, 03:03
OK linus/axs101_defconfig/arcompact Sat Oct 20, 03:03 http://kisskb.ellerman.id.au/kisskb/buildresult/13556495/ Commit: Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2a96661054452c3016c377d72a38c6d4948ea6ae Compiler: arc-buildroot-linux-uclibc-gcc (Buildroot 2015.08.1) 4.8.4 No errors found in log Possible warnings (3) -- include/linux/kernel.h:845:29: warning: comparison of distinct pointer types lacks a cast [enabled by default] arch/arc/include/asm/cmpxchg.h:95:29: warning: value computed is not used [-Wunused-value] net/ipv4/tcp_input.c:4319:49: warning: array subscript is above array bounds [-Warray-bounds] ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
[RFC] ARC: ARCv2: Introduce SmaRT support : lmbench results
Lmbench summary with enabled and disabled SmaRT support is attached. -- Eugeniy Paltsev L M B E N C H 3 . 0 S U M M A R Y (Alpha software, do not distribute) Basic system parameters -- Host OS Description Mhz tlb cache mem scal pages line par load bytes - - --- - - -- ena Linux 4.19.0- ena 1000 8 128 1.75001 ena Linux 4.19.0- ena 1000 8 1.75001 ena Linux 4.19.0- ena 1000 8 1.73001 ena Linux 4.19.0- ena 1000 8 128 1.75001 dis Linux 4.19.0- dis 1000 8 1.74001 dis Linux 4.19.0- dis 1000 8 1.75001 dis Linux 4.19.0- dis 1000 8 128 1.75001 dis Linux 4.19.0- dis 1000 8 1.74001 Processor, Processes - times in microseconds - smaller is better -- Host OS Mhz null null open slct sig sig fork exec sh call I/O stat clos TCP inst hndl proc proc proc - - ena Linux 4.19.0- 1000 0.38 0.59 2.46 4.87 23.4 0.55 2.20 388. 1975 3673 ena Linux 4.19.0- 1000 0.38 0.59 2.45 4.90 23.4 0.55 2.20 366. 1979 3671 ena Linux 4.19.0- 1000 0.38 0.59 2.44 4.89 23.4 0.55 2.19 381. 1961 3696 ena Linux 4.19.0- 1000 0.38 0.59 2.43 5.22 23.4 0.55 2.18 388. 1972 3702 dis Linux 4.19.0- 1000 0.39 0.61 2.53 4.71 23.6 0.55 2.20 311. 1793 3370 dis Linux 4.19.0- 1000 0.39 0.59 2.55 4.74 23.6 0.55 2.20 311. 1807 3363 dis Linux 4.19.0- 1000 0.39 0.59 2.55 4.77 23.5 0.58 2.20 314. 1787 3373 dis Linux 4.19.0- 1000 0.39 0.59 2.54 4.78 23.5 0.61 2.20 314. 1786 3395 Basic integer operations - times in nanoseconds - smaller is better --- Host OS intgr intgr intgr intgr intgr bit addmuldivmod - - -- -- -- -- -- ena Linux 4.19.0- 1. 0.5500 13.0 8. ena Linux 4.19.0- 1. 0.5500 13.0 8.0100 ena Linux 4.19.0- 1. 0.5500 13.0 8.0100 ena Linux 4.19.0- 1. 0.5500 13.0 8. dis Linux 4.19.0- 1. 0.5500 13.0 8. dis Linux 4.19.0- 1. 0.5500 13.0 8. dis Linux 4.19.0- 1. 0.5500 13.0 8. dis Linux 4.19.0- 1. 0.5500 13.0 8. Basic uint64 operations - times in nanoseconds - smaller is better -- Host OS int64 int64 int64 int64 int64 bitaddmuldivmod - - -- -- -- -- -- ena Linux 4.19.0-11. 10.3 116.2 97.0 ena Linux 4.19.0-12. 10.3 116.2 96.4 ena Linux 4.19.0-11. 10.3 116.2 96.5 ena Linux 4.19.0-11. 10.3 116.2 96.4 dis Linux 4.19.0-12. 10.3 116.2 96.4 dis Linux 4.19.0-11. 10.3 116.2 96.4 dis Linux 4.19.0-11. 10.3 116.2 96.5 dis Linux 4.19.0-11. 10.3 116.2 96.4 Basic float operations - times in nanoseconds - smaller is better - Host OS float float float float addmuldivbogo - - -- -- -- -- ena Linux 4.19.0- 145.2 144.7 288.2 730.9 ena Linux 4.19.0- 145.9 144.6 288.0 729.0 ena Linux 4.19.0- 145.9 144.7 288.2 730.2 ena Linux 4.19.0- 145.9 144.7 288.2 729.6 dis Linux 4.19.0- 146.0 144.6 288.3 730.2 dis Linux 4.19.0- 145.2 144.7 288.2 729.0 dis Linux 4.19.0- 145.4 144.7 288.2 729.9 dis Linux 4.19.0- 146.0 144.7 288.2 765.1 Basic double operations - times in nanoseconds - smaller is better -- Host
