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--- gdb [2015/11/04 13:09] – niziak
+++ gdb [2025/05/28 07:16] (current) – [stepping] niziak
@@ Line 1: / Line 1: @@
+====== GDB ======
+====== Starting  ======
+<code>
+gdb <executable>
+gdb --args <executable> arg1 arg2 arg3
+gdb -x gdbcommands --init-commands=gdb-openocd.cfg
+</code>
+====== Symbols and paths =====
+Add symbols:
+<code>
+symbol-file /mnt/nfs/binary-with-symbols.elf
+dir /mnt/nfs/src
+</code>
+====== Using ======
 ==== getting info ====
-  * p[rint] var
+set print pretty on
+  * p[rint] <name> - print value
+    * p * <name> - print what is pointed by
+    * p/x <name> - print in hex format
+    * p <name> @<n> print <n> values starting at <name>
+    * p <chars> <TAB> - List all variables starting with <chars>
+    * p ((sturct dummy*)variable)[0] - Dump structure members
+  * ptype var
   * x /100bx m - eXamine memory located by variable m, print 100 bytes in hex format
   * bt (backtrace)
   * t (threads)
+==== call stack ====
+  * bt (backtrace)
+  * frame 4 - switch to frame #4
+  * up
+  * down
 ==== breakpoints ====
-  * break malloc
+  * b[reak] malloc
+  * b mall <TAB> - List all starting with mall
   * clear malloc
+  * info break
+    * i[nfo] b
+  * dis[able] 1 - disable brakpoint 1
+  * en[able] 1
+  * d[elete] 1
+  * d 1 2
+  * d - delete all breakpoints
+  * cond[ition] 1 <expr> - stop at breakpoint 1 only if <expr> is true
+  * cond 1 - Remove condition from breakpoint 1
+Add to C code to catch timing critical issues:
+<code c>
+if (p_queue->p_cb->locked) {
+  __BKPT(8);
+}
+</code>
 ==== stepping ====
-  * s[tep]
-  * c[ontinue] <num_to_ignore>
+  * **s** [tep] - step to next **source** line
-  * n[ext] - to next line
+  * **c** [ontinue] <num_to_ignore>
-  * fin[ish] - execute until stack frame returns
+  * **n** [ext] - step (do not enter to subroutines)
-  * u[ntil] <line number> - execute to line (to avoid loops)
+  * **fin** [ish] - execute until stack frame returns
+  * **u** [ntil] <line number> - execute to line (to avoid loops)
+Skip current command:
+<code>
+tbreak +1
+jump +1
+</code>
+==== infos ====
+  * show debug-file-directory
+==== threads ====
+  * info threads - show info about threads
+  * thread 4 - switch to thread 4
+  * print mutex
+  * info line - print current code line
+  * frame - print current execution position and code
+==== OpenOCD ====
+Disable Cortex M0 interrupts
+  * mon cortex_m maskisr on
+<code>
+set remote hardware-breakpoint-limit 4
+set remote hardware-watchpoint-limit 2
+define hook-step
+mon cortex_m maskisr on
+end
+define hookpost-step
+mon cortex_m maskisr off
+end
+</code>
+===== gdbcommands file =====
+<file | gdbcommands>
+set verbose on
+set auto-load safe-path /
+set debug auto-load on
+set sysroot /home/user/prj/buildroot/output/target
+source ../../interactive/src
+set substitute-path /usr/sbin/app /apps/app/app
+add-symbol-file /home/user/prj/stm32/main/bootloader/build/bin/main.elf 0x08005000
+dir ../../out/build/app-undefined
+dir ../../out/build/app-undefined/apps/app
+dir ../../out/build/app-undefined/apps/app/app
+set substitute-path /usr/lib ../../out/target/usr/lib
+set args -m 0 -c /etc/conf.d/conf.xml
+#sharedlibrary
+#target extended-remote 192.168.1.62:12345
+break myFunction
+</file>
+<file | gdb-openocd.cfg>
+target extended-remote localhost:2331
+#monitor reset
+monitor halt
+# Setup GDB FOR FASTER DOWNLOADS
+#set remote memory-write-packet-size 1024
+#set remote memory-write-packet-size fixed
+</file>
+<file>
+# Add GDB access to mem range where VTOR is located
+mem 0xE0000000 0xE00FFFFF
+define bootapp
+  monitor reset halt
+  # Adjust VTOR (Vector table offset register)
+  set {int}0xE000ED08 = &exception_table
+  # Set SP/PC to the values from the actual vector table
+  set $sp = *(int*)&exception_table
+  set $pc = *((int*)(&exception_table)+1)
+end
+</file>
+==== symbols ====
+  * set symbol-reloading on
+  * add-symbol-file ~/mymodule.o 0xd8be4000
+  * add-symbol-file ~/myanother.o 0x12341234
+  * set debug-file-directory <directory> - set directory contain symbol file
+  * show debug-file-directory
 ==== file paths and libraries ====
@@ Line 23: / Line 162: @@
   * set sysroot /home/niziak/n/3/out/host/usr/arm-buildroot-linux-uclibcgnueabi/sysroot
-=== source paths ===
+==== source paths ====
 Search paths (prefixes):
   * dir /path/to/src1
@@ Line 30: / Line 169: @@
 Translate beginning of paths:
   * set substitute-path /usr/lib ../../out/target/usr/lib
+====== Kernel OOPS ======
+=== Reading ===
+<code>
+PC is at RTMPCheckEtherType+0x90/0x4d4 [mt7601Uapsta]
+LR is at RTMPCheckEtherType+0x34/0x4d4 [mt7601Uapsta]
+Code: e59f3418 e0256593 e2859d43 e289902c (e5d939ba)
+</code>
+Oops occurs at offset 0x90 from RTMPCheckEtherType. 0x4d4 is length.
+"Code" line shows last instruction. Instruction in bracket is problematic instruction (at RTMPCheckEtherType+0x90)
+=== Tracing ===
+Disassembly kernel binary or module binary:
+objdump -dS vmlinux > /tmp/kernel.s
+and look into generated code.
+====== Python ======
+<code bash>apt-get install gdb python2.7-dbg</code>
+<code bash>gdb python <pid></code>
+====== DRAFTS ======
+call raise(kernel-thread-id, signo) or call pthread_kill(pthread-thread-id, signo).

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