summaryrefslogtreecommitdiffstats
path: root/bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch
diff options
context:
space:
mode:
Diffstat (limited to 'bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch')
-rw-r--r--bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch334
1 files changed, 334 insertions, 0 deletions
diff --git a/bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch b/bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch
new file mode 100644
index 00000000..3734675b
--- /dev/null
+++ b/bsp/meta-synopsys/recipes-kernel/linux/linux-arc/2001-ARC-prevent-showing-irrelevant-exception-info-in-sig.patch
@@ -0,0 +1,334 @@
+From 3f9fab23bfd4fc2d41df6aaf52855d6bae91d3e5 Mon Sep 17 00:00:00 2001
+From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+Date: Thu, 15 Nov 2018 13:07:12 +0300
+Subject: [PATCH 1/3] ARC: prevent showing irrelevant exception info in signal
+ message
+
+We process signals in the end of syscall/exception handler.
+If 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 @ 0x00000000 by insn @ 0x000123ec
+ [EFA ]: 0x00000000
+ [BLINK ]: 0x123ea
+ [ERET ]: 0x123ec
+ @off 0x123ec in [/home/waitpid02]
+ VMA: 0x00010000 to 0x00016000
+ [STAT32]: 0x80080882 : IE U
+ BTA: 0x000123ea SP: 0x5ffd3db0 FP: 0x00000000
+ LPS: 0x20031684 LPE: 0x2003169a LPC: 0x00000006
+ [-----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-rc8-00002-gde0f6d6aeb53-dirty #17
+ [ECR ]: 0x00050100
+ [EFA ]: 0x00000000
+ [BLINK ]: 0x20001486
+ [-----other-info-----]
+_____________________________
+
+This patch fix
+STAR 9001146055: waitpid02: Invalid Write @ 0x00000000 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 @ 0x00000000 by insn @ 0x2003a35c
+potentially unexpected fatal signal 11.
+Path: /root/arc_hell
+CPU: 1 PID: 103 Comm: arc_hell Not tainted 4.18.0-rc8-00002-gde0f6d6aeb53-dirty #17
+[ECR ]: 0x00050100
+[EFA ]: 0x00000000
+[BLINK ]: 0x20039ef8
+[ERET ]: 0x2003a35c
+[STAT32]: 0x80080882 : IE U
+BTA: 0x2003a358 SP: 0x5fa27dc4 FP: 0x5fa27de8
+LPS: 0x2003a628 LPE: 0x2003a62c LPC: 0x00000000
+r00: 0x00000000 r01: 0x200740b0 r02: 0x00000001
+r03: 0x00000007 r04: 0x80808080 r05: 0x2f2f2f2f
+r06: 0x7c7a2f43 r07: 0x00000000 r08: 0x1a131100
+r09: 0x2008b1e0 r10: 0x20003a5c r11: 0x20004038
+r12: 0x20039ef8 r13: 0x200740b0 r14: 0x00000000
+r15: 0x200740b0 r16: 0x00000000 r17: 0x0007d468
+r18: 0x0009313a r19: 0x00000000 r20: 0x0009c22c
+r21: 0x0009c23c r22: 0x0009ab64 r23: 0x00000000
+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 @ 0x00000000 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-rc8-00002-gde0f6d6aeb53-dirty #17
+[ECR ]: 0x00050100
+[EFA ]: 0x00000000
+[BLINK ]: 0x20001486
+[ERET ]: 0x2000146c
+[STAT32]: 0x80080082 : IE U
+BTA: 0x20000fc4 SP: 0x5fa21d64 FP: 0x00000000
+LPS: 0x200524a0 LPE: 0x200524b6 LPC: 0x00000006
+r00: 0x2000c0dc r01: 0x00000018 r02: 0x0001159a
+r03: 0x00000001 r04: 0x00000000 r05: 0x00000045
+r06: 0x0000004e r07: 0x01010101 r08: 0x000000dc
+r09: 0x200a31e0 r10: 0x20003a5c r11: 0x20004038
+r12: 0x20001486 r13: 0x20004174 r14: 0x07ca2bc0
+r15: 0x20004078 r16: 0x00000000 r17: 0x20004038
+r18: 0x00000001 r19: 0x00000000 r20: 0x0001159a
+r21: 0x00000001 r22: 0x00000000 r23: 0x00000004
+r24: 0x2000d1fc r25: 0x20004cd0
+------------>8---------------
+
+3) Process killed by signal (waitpid02 test), print-fatal-signals == 0:
+------------>8---------------
+ # ./waitpid02
+------------>8---------------
+
+4) NULL pointer access from kernel space, regardless print-fatal-signals
+value:
+------------>8---------------
+Oops
+Exception: at stmmac_dvr_probe+0x40/0x7e0:
+ ECR: 0x00050200 => Invalid Write @ 0x00000000 by insn @ 0x90575254
+Path: (null)
+CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc8-00002-gde0f6d6aeb53-dirty #11
+[EFA ]: 0x00000000
+[BLINK ]: stmmac_dvr_probe+0x2a/0x7e0
+[ERET ]: stmmac_dvr_probe+0x40/0x7e0
+[STAT32]: 0x80080402 : IE K
+BTA: 0x9057523e SP: 0xbf02be40 FP: 0x00000000
+LPS: 0x9073dbcc LPE: 0x9073dbe0 LPC: 0x00000000
+r00: 0xbf1f0000 r01: 0x00000000 r02: 0x00000008
+r03: 0x00000000 r04: 0x00000064 r05: 0x00000000
+r06: 0x00000003 r07: 0x00000004 r08: 0x01010101
+r09: 0x00000031 r10: 0xbf1f0006 r11: 0x00000000
+r12: 0x9057523e
+
+Stack Trace:
+ stmmac_dvr_probe+0x40/0x7e0
+ dwmac_generic_probe+0x50/0xbc
+ platform_drv_probe+0x26/0x5c
+ really_probe+0x3b0/0x464
+ __driver_attach+0xd4/0xd8
+ bus_for_each_dev+0x3a/0x70
+ bus_add_driver+0x12a/0x18c
+ driver_register+0x56/0xe8
+ do_one_initcall+0x2e/0x118
+ kernel_init_freeable+0x102/0x194
+------------>8---------------
+
+Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+---
+ arch/arc/include/asm/bug.h | 1 +
+ arch/arc/kernel/traps.c | 3 +++
+ arch/arc/kernel/troubleshoot.c | 51 +++++++++++++++++++++++++++++++++---------
+ arch/arc/mm/fault.c | 8 +++++++
+ 4 files changed, 52 insertions(+), 11 deletions(-)
+
+diff --git a/arch/arc/include/asm/bug.h b/arch/arc/include/asm/bug.h
+index 21ec82466d62..b68f7f82f2d8 100644
+--- a/arch/arc/include/asm/bug.h
++++ b/arch/arc/include/asm/bug.h
+@@ -16,6 +16,7 @@
+ struct task_struct;
+
+ void show_regs(struct pt_regs *regs);
++void show_exception_mesg(struct pt_regs *regs);
+ void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs);
+ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
+ unsigned long address);
+diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
+index b123558bf0bb..e66fd40296b3 100644
+--- a/arch/arc/kernel/traps.c
++++ b/arch/arc/kernel/traps.c
+@@ -49,6 +49,9 @@ unhandled_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
+
+ tsk->thread.fault_address = (__force unsigned int)info->si_addr;
+
++ if (unhandled_signal(tsk, info->si_signo))
++ show_exception_mesg(regs);
++
+ force_sig_info(info->si_signo, info, tsk);
+
+ } else {
+diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
+index e8d9fb452346..fdfba1942a06 100644
+--- a/arch/arc/kernel/troubleshoot.c
++++ b/arch/arc/kernel/troubleshoot.c
+@@ -101,13 +101,13 @@ static void show_faulting_vma(unsigned long address, char *buf)
+ if (IS_ERR(nm))
+ nm = "?";
+ }
+- pr_info(" @off 0x%lx in [%s]\n"
+- " VMA: 0x%08lx to 0x%08lx\n",
++
++ pr_cont("[off 0x%lx in %s, VMA: %08lx:%08lx] ",
+ vma->vm_start < TASK_UNMAPPED_BASE ?
+ address : address - vma->vm_start,
+ nm, vma->vm_start, vma->vm_end);
+ } else
+- pr_info(" @No matching VMA found\n");
++ pr_cont("[No matching VMA found] ");
+
+ up_read(&active_mm->mmap_sem);
+ }
+@@ -117,7 +117,7 @@ static void show_ecr_verbose(struct pt_regs *regs)
+ unsigned int vec, cause_code;
+ unsigned long address;
+
+- pr_info("\n[ECR ]: 0x%08lx => ", regs->event);
++ pr_cont("\n ECR: 0x%08lx => ", regs->event);
+
+ /* For Data fault, this is data address not instruction addr */
+ address = current->thread.fault_address;
+@@ -165,10 +165,42 @@ static void show_ecr_verbose(struct pt_regs *regs)
+ }
+ }
+
++static inline void show_exception_mesg_u(struct pt_regs *regs)
++{
++ struct task_struct *tsk = current;
++ char *buf;
++
++ pr_info("Exception: %s[%d]: at %pS ",
++ tsk->comm, task_pid_nr(tsk), (void *)regs->ret);
++
++ buf = (char *)__get_free_page(GFP_NOWAIT);
++ if (buf) {
++ show_faulting_vma(regs->ret, buf);
++ free_page((unsigned long)buf);
++ }
++
++ show_ecr_verbose(regs);
++}
++
++static inline void show_exception_mesg_k(struct pt_regs *regs)
++{
++ pr_info("Exception: at %pS:", (void *)regs->ret);
++
++ show_ecr_verbose(regs);
++}
++
+ /************************************************************************
+ * API called by rest of kernel
+ ***********************************************************************/
+
++void show_exception_mesg(struct pt_regs *regs)
++{
++ if (user_mode(regs))
++ show_exception_mesg_u(regs);
++ else
++ show_exception_mesg_k(regs);
++}
++
+ void show_regs(struct pt_regs *regs)
+ {
+ struct task_struct *tsk = current;
+@@ -182,15 +214,10 @@ void show_regs(struct pt_regs *regs)
+ print_task_path_n_nm(tsk, buf);
+ show_regs_print_info(KERN_INFO);
+
+- show_ecr_verbose(regs);
+-
+- pr_info("[EFA ]: 0x%08lx\n[BLINK ]: %pS\n[ERET ]: %pS\n",
+- current->thread.fault_address,
++ pr_info("[ECR ]: 0x%08lx\n[EFA ]: 0x%08lx\n[BLINK ]: %pS\n[ERET ]: %pS\n",
++ regs->event, current->thread.fault_address,
+ (void *)regs->blink, (void *)regs->ret);
+
+- if (user_mode(regs))
+- show_faulting_vma(regs->ret, buf); /* faulting code, not data */
+-
+ pr_info("[STAT32]: 0x%08lx", regs->status32);
+
+ #define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""
+@@ -233,6 +260,8 @@ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
+ /* Show fault description */
+ pr_info("\n%s\n", str);
+
++ show_exception_mesg(regs);
++
+ /* Caller and Callee regs */
+ show_regs(regs);
+
+diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
+index db6913094be3..026d662a7668 100644
+--- a/arch/arc/mm/fault.c
++++ b/arch/arc/mm/fault.c
+@@ -203,6 +203,10 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void __user *)address;
++
++ if (unhandled_signal(tsk, info.si_signo))
++ show_exception_mesg(regs);
++
+ force_sig_info(SIGSEGV, &info, tsk);
+ return;
+ }
+@@ -242,5 +246,9 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
+ info.si_errno = 0;
+ info.si_code = BUS_ADRERR;
+ info.si_addr = (void __user *)address;
++
++ if (unhandled_signal(tsk, info.si_signo))
++ show_exception_mesg(regs);
++
+ force_sig_info(SIGBUS, &info, tsk);
+ }
+--
+2.16.2
+