Changes between Version 10 and Version 11 of Dev/KernelHack/COINS/worklog/201111

Timestamp:

Nov 25, 2011 2:02:13 AM (13 years ago)

Author:

mitty

Comment:

--

Dev/KernelHack/COINS/worklog/201111

@@ -1971 +1971 @@
 $14 = 0x4855c3c9e11ca49c
 }}}
+
+ = 11/21 =
+ == check backtrace to stackmod_read ==
+ * s0711489@ubuntu-lucid64:~$ sudo insmod stackmod.ko
+ * s0711489@ubuntu-lucid64:~$ sudo mknod /dev/stack c 251 0
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+ * s0711489@ubuntu-lucid64:~$ tail /var/log/kern.log
+{{{
+Nov 21 06:41:49 ubuntu-lucid64 kernel: [ 5352.251306] stackmod is loaded
+Nov 21 06:41:49 ubuntu-lucid64 kernel: [ 5352.251310] stackmod: 128 entry, major is 251, minor is 0
+Nov 21 06:41:49 ubuntu-lucid64 kernel: [ 5352.251323] stackmod: create /proc/stackmod
+Nov 21 06:41:49 ubuntu-lucid64 kernel: [ 5352.251325] stackmod is added successfully
+Nov 21 06:42:03 ubuntu-lucid64 kernel: [ 5366.796334] stackmod is opened
+Nov 21 06:42:03 ubuntu-lucid64 kernel: [ 5366.796353] stackmod is read
+Nov 21 06:42:03 ubuntu-lucid64 kernel: [ 5366.796357] stackmod is released
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.text
+{{{
+0xffffffffa0062000
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.data
+{{{
+0xffffffffa0062478
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.bss
+{{{
+0xffffffffa00626b0
+}}}
+
+ * gdb
+{{{
+(gdb) file vmlinux
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/vmlinux...(no debugging symbols found)...done.
+(gdb) add-symbol-file ../../04/stackmod/stackmod.o 0xffffffffa0062000 -s .data 0xffffffffa0062478 -s .bss 0xffffffffa00626b0
+add symbol table from file "../../04/stackmod/stackmod.o" at
+        .text_addr = 0xffffffffa0062000
+        .data_addr = 0xffffffffa0062478
+        .bss_addr = 0xffffffffa00626b0
+(y or n) y
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.o...done.
+(gdb) target remote localhost:8864
+Remote debugging using localhost:8864
+0xffffffff810097a9 in native_safe_halt ()
+    at /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/arch/x86/include/asm/irqflags.h:49
+49              asm volatile("sti; hlt": : :"memory");
+(gdb) b stackmod_read
+Breakpoint 1 at 0xffffffffa0062016: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 56.
+(gdb) c
+Continuing.
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+Breakpoint 1, stackmod_read (filep=0xffff88001efcf900,
+    buf_user=0xde9000 <Address 0xde9000 out of bounds>, size=32768,
+    offset=0xffff88001aecdf48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:56
+56      ) {
+(gdb) bt
+#0  stackmod_read (filep=0xffff88001efcf900,
+    buf_user=0xde9000 <Address 0xde9000 out of bounds>, size=32768,
+    offset=0xffff88001aecdf48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:56
+#1  0xffffffff810df784 in vfs_read (file=0xffff88001efcf900,
+    buf=0xde9000 <Address 0xde9000 out of bounds>, count=32768,
+    pos=0xffff88001aecdf48) at fs/read_write.c:310
+#2  0xffffffff810dfa2b in sys_read (fd=<value optimized out>,
+    buf=0xde9000 <Address 0xde9000 out of bounds>, count=32768)
+    at fs/read_write.c:400
+#3  0xffffffff810029eb in ?? ()
+#4  0x0000000000000246 in stackmod_exit ()
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:175
+Backtrace stopped: previous frame inner to this frame (corrupt stack?)
+}}}
+
+ == implement read/write for char dev ==
+ * [http://www.mech.tohoku-gakuin.ac.jp/rde/contents/linux/drivers/chardev1.html 簡単なキャラクタデバイスをつくる]
+ * 参考
+  * drivers/char/mem.c -> read_zero, write_null
+   * access_ok
+  * drivers/char/nvram.c -> nvram_read, nvram_write
+   * loff_t *ppos
+  * drivers/char/tpm/tpm.c -> tpm_read, tpm_write
+
+ * s0711489@ubuntu-lucid64:~$ sudo insmod stackmod.ko
+{{{
+Nov 21 17:33:19 ubuntu-lucid64 kernel: [   53.780695] stackmod is loaded
+Nov 21 17:33:19 ubuntu-lucid64 kernel: [   53.780699] stackmod: 128 entry, major is 251, minor is 0
+Nov 21 17:33:19 ubuntu-lucid64 kernel: [   53.780707] stackmod: create /proc/stackmod
+Nov 21 17:33:19 ubuntu-lucid64 kernel: [   53.780709] stackmod is added successfully
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ sudo mknod /dev/stack c 251 0
+ * s0711489@ubuntu-lucid64:~$ ls -l /dev/stack
+ * s0711489@ubuntu-lucid64:~$ sudo chmod 666 /dev/stack
+
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+{{{
+Nov 21 17:34:37 ubuntu-lucid64 kernel: [  131.432249] stackmod is opened
+Nov 21 17:34:37 ubuntu-lucid64 kernel: [  131.432286] stackmod is written
+Nov 21 17:34:37 ubuntu-lucid64 kernel: [  131.432292] stackmod is released
+}}}
+ * s0711489@ubuntu-lucid64:~$ echo fuga > /dev/stack
+{{{
+Nov 21 17:34:50 ubuntu-lucid64 kernel: [  144.556110] stackmod is opened
+Nov 21 17:34:50 ubuntu-lucid64 kernel: [  144.556125] stackmod is written
+Nov 21 17:34:50 ubuntu-lucid64 kernel: [  144.556136] stackmod is released
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+fuga
+���hoge
+���s0711489@ubuntu-lucid64:~$
+}}}
+{{{
+Nov 21 17:35:16 ubuntu-lucid64 kernel: [  170.887727] stackmod is opened
+Nov 21 17:35:16 ubuntu-lucid64 kernel: [  170.887745] stackmod is read
+Nov 21 17:35:16 ubuntu-lucid64 kernel: [  170.887758] stackmod is read
+Nov 21 17:35:16 ubuntu-lucid64 kernel: [  170.887763] stackmod is read
+Nov 21 17:35:16 ubuntu-lucid64 kernel: [  170.887766] stackmod is released
+}}}
+  * buggy
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 0
+}}}
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 1
+}}}
+ * s0711489@ubuntu-lucid64:~$ echo fuga > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 2
+}}}
+ * s0711489@ubuntu-lucid64:~$ echo piyo > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 3
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+piyo
+���fuga
+���hoge
+���s0711489@ubuntu-lucid64:~$
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 0
+}}}
+
+ === check what is bug with gdb ===
+ * s0711489@ubuntu-lucid64:~$ sudo insmod stackmod.ko
+ * s0711489@ubuntu-lucid64:~$ sudo mknod /dev/stack c 251 0
+ * s0711489@ubuntu-lucid64:~$ sudo chmod 666 /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.text
+{{{
+0xffffffffa0056000
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.data
+{{{
+0xffffffffa0056738
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.bss
+{{{
+0xffffffffa0056970
+}}}
+
+ * gdb
+{{{
+(gdb) file vmlinux
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/vmlinux...(no debugging symbols found)...done.
+(gdb) add-symbol-file ../../04/stackmod/stackmod.o 0xffffffffa0056000 -s .data 0xffffffffa0056738 -s .bss 0xffffffffa0056970
+add symbol table from file "../../04/stackmod/stackmod.o" at
+        .text_addr = 0xffffffffa0056000
+        .data_addr = 0xffffffffa0056738
+        .bss_addr = 0xffffffffa0056970
+(y or n) y
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.o...done.
+(gdb) b stackmod_proc_read
+Cannot access memory at address 0xffffffffa00561e0
+(gdb) target remote localhost:8864
+Remote debugging using localhost:8864
+0xffffffff810097a9 in native_safe_halt ()
+    at /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/arch/x86/include/asm/irqflags.h:49
+49              asm volatile("sti; hlt": : :"memory");
+(gdb) b stackmod_proc_read
+Breakpoint 1 at 0xffffffffa00561e0: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 137.
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 0
+}}}
+{{{
+Breakpoint 1, stackmod_proc_read (page=0xffff88001f792000 "0\"y\037",
+    start=0xffff88001b6d1e90, off=0, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p stack
+$1 = {buffer = 0xffff88001b6e5000, depth = 0, errno = 0}
+(gdb) p/x stack.buffer
+$2 = 0xffff88001b6e5000
+(gdb) p/x stack.buffer[0]
+$3 = 0x0
+(gdb) p/x stack.buffer[1]
+$4 = 0x0
+(gdb) c
+Continuing.
+
+Breakpoint 1, stackmod_proc_read (page=0xffff88001f792000 "stack: 0\n",
+    start=0xffff88001b6d1e90, off=9, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p/x stack.buffer
+$5 = 0xffff88001b6e5000
+(gdb) p stack
+$6 = {buffer = 0xffff88001b6e5000, depth = 0, errno = 0}
+(gdb) p/x stack.buffer[0]
+$7 = 0x0
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 1
+}}}
+{{{
+Breakpoint 1, stackmod_proc_read (page=0xffff88001f7a3000 "@5z\037",
+    start=0xffff88001b6d1e90, off=0, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p stack
+$8 = {buffer = 0xffff88001b6e5000, depth = 1, errno = 0}
+(gdb) p/x stack.buffer
+$9 = 0xffff88001b6e5000
+(gdb) p/x stack.buffer[0]
+$10 = 0xffff880017ea1340
+(gdb) p stack.buffer[0]
+$11 = 0xffff880017ea1340 "hoge\n\210\377\377"
+(gdb) p stack.buffer[1]
+$12 = 0x0
+(gdb) bt
+#0  stackmod_proc_read (page=0xffff88001f7a3000 "@5z\037",
+    start=0xffff88001b6d1e90, off=0, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+#1  0xffffffff811291f4 in __proc_file_read (file=<value optimized out>,
+    buf=0x2398000 <Address 0x2398000 out of bounds>, nbytes=32768,
+    ppos=0xffff88001b6d1f48) at fs/proc/generic.c:120
+#2  proc_file_read (file=<value optimized out>,
+    buf=0x2398000 <Address 0x2398000 out of bounds>, nbytes=32768,
+    ppos=0xffff88001b6d1f48) at fs/proc/generic.c:201
+#3  0xffffffff81124b07 in proc_reg_read (file=0xffff88001aeda840,
+    buf=0x2398000 <Address 0x2398000 out of bounds>, count=32768,
+    ppos=0xffff88001b6d1f48) at fs/proc/inode.c:163
+#4  0xffffffff810df784 in vfs_read (file=0xffff88001aeda840,
+    buf=0x2398000 <Address 0x2398000 out of bounds>, count=0,
+    pos=0xffff88001b6d1f48) at fs/read_write.c:310
+#5  0xffffffff810dfa2b in sys_read (fd=<value optimized out>,
+    buf=0x2398000 <Address 0x2398000 out of bounds>, count=32768)
+    at fs/read_write.c:400
+#6  0xffffffff810029eb in ?? ()
+#7  0x0000000000000246 in ?? ()
+#8  0x00007fffe2db44d0 in ?? ()
+#9  0x0000000000000000 in ?? ()
+(gdb) c
+Continuing.
+
+Breakpoint 1, stackmod_proc_read (page=0xffff88001f7a3000 "stack: 1\n",
+    start=0xffff88001b6d1e90, off=9, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) bt
+#0  stackmod_proc_read (page=0xffff88001f7a3000 "stack: 1\n",
+    start=0xffff88001b6d1e90, off=9, count=3072, eof=0xffff88001b6d1e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+#1  0xffffffff811291f4 in __proc_file_read (file=<value optimized out>,
+    buf=0x2398000 "stack: 1\n", nbytes=32768, ppos=0xffff88001b6d1f48)
+    at fs/proc/generic.c:120
+#2  proc_file_read (file=<value optimized out>, buf=0x2398000 "stack: 1\n",
+    nbytes=32768, ppos=0xffff88001b6d1f48) at fs/proc/generic.c:201
+#3  0xffffffff81124b07 in proc_reg_read (file=0xffff88001aeda840,
+    buf=0x2398000 "stack: 1\n", count=32768, ppos=0xffff88001b6d1f48)
+    at fs/proc/inode.c:163
+#4  0xffffffff810df784 in vfs_read (file=0xffff88001aeda840,
+    buf=0x2398000 "stack: 1\n", count=9, pos=0xffff88001b6d1f48)
+    at fs/read_write.c:310
+#5  0xffffffff810dfa2b in sys_read (fd=<value optimized out>,
+    buf=0x2398000 "stack: 1\n", count=32768) at fs/read_write.c:400
+#6  0xffffffff810029eb in ?? ()
+#7  0x0000000000000246 in ?? ()
+#8  0x00007fffe2db44a0 in ?? ()
+#9  0x0000000000000000 in ?? ()
+(gdb) c
+Continuing.
+
+(gdb) d
+Delete all breakpoints? (y or n) y
+(gdb) b stackmod.c:144
+
+Breakpoint 2 at 0xffffffffa0056216: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 144.
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 3
+}}}
+{{{
+Breakpoint 2, stackmod_proc_read (page=<value optimized out>,
+    start=<value optimized out>, off=<value optimized out>,
+    count=<value optimized out>, eof=0xffff88001ee0de9c,
+    data=<value optimized out>)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:146
+146     }
+(gdb) p len
+No symbol "len" in current context.
+(gdb) p outlen
+$13 = <value optimized out>
+(gdb) p page
+$14 = <value optimized out>
+(gdb) finish
+Run till exit from #0  stackmod_proc_read (page=<value optimized out>,
+    start=<value optimized out>, off=<value optimized out>,
+    count=<value optimized out>, eof=0xffff88001ee0de9c,
+    data=<value optimized out>)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:146
+__proc_file_read (file=<value optimized out>,
+    buf=0x659000 <Address 0x659000 out of bounds>, nbytes=32768,
+    ppos=0xffff88001ee0df48) at fs/proc/generic.c:125
+125                     if (n == 0)   /* end of file */
+Could not fetch register "orig_rax"; remote failure reply 'E00'
+(gdb) c
+Continuing.
+
+Breakpoint 2, stackmod_proc_read (page=<value optimized out>,
+    start=<value optimized out>, off=<value optimized out>,
+    count=<value optimized out>, eof=0xffff88001ee0de9c,
+    data=<value optimized out>)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:146
+146     }
+(gdb) c
+Continuing.
+
+(gdb) d
+Delete all breakpoints? (y or n) y
+(gdb) b stackmod_proc_read
+
+Breakpoint 3 at 0xffffffffa00561e0: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 137.
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 3
+}}}
+{{{
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 3\n",
+    start=0xffff88001b669e90, off=0, count=3072, eof=0xffff88001b669e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p outlen
+$15 = <value optimized out>
+(gdb) ret
+Make stackmod_proc_read return now? (y or n) y
+Could not fetch register "orig_rax"; remote failure reply 'E00'
+(gdb) c
+Continuing.
+
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 3\n",
+    start=0xffff88001b669e90, off=9, count=3072, eof=0xffff88001b669e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 4
+}}}
+{{{
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 3\n",
+    start=0xffff88001b669e90, off=0, count=3072, eof=0xffff88001b669e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p stack
+$16 = {buffer = 0xffff88001b6e5000, depth = 4, errno = 0}
+(gdb) p/x stack.buffer
+$17 = 0xffff88001b6e5000
+(gdb) p/x stack.buffer[0]
+$18 = 0xffff880017ea1340
+(gdb) p/x stack.buffer[4]
+$19 = 0x0
+(gdb) p stack.buffer[0]
+$20 = 0xffff880017ea1340 "hoge\n\210\377\377"
+(gdb) p stack.buffer[1]
+$21 = 0xffff880017ea1640 "hoge\n\210\377\377"
+(gdb) p stack.buffer[2]
+$22 = 0xffff880017ea1200 "hoge\n\210\377\377"
+(gdb) p stack.buffer[3]
+$23 = 0xffff88001ef2cd80 "hoge\n\210\377\377\210\315\362\036"
+(gdb) p stack.buffer[4]
+$24 = 0x0
+(gdb) c
+Continuing.
+
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 4\n",
+    start=0xffff88001b669e90, off=9, count=3072, eof=0xffff88001b669e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+hoge
+������hoge
+���hoge
+���hoge
+���s0711489@ubuntu-lucid64:~$
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 0
+}}}
+{{{
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 4\n",
+    start=0xffff88001afd5e90, off=0, count=3072, eof=0xffff88001afd5e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) p stack
+$25 = {buffer = 0xffff88001b6e5000, depth = 0, errno = 0}
+(gdb) p stack.buffer[0]
+$26 = 0x0
+(gdb) p stack.buffer[3]
+$27 = 0x0
+(gdb) c
+Continuing.
+
+Breakpoint 3, stackmod_proc_read (page=0xffff88001f792000 "stack: 0\n",
+    start=0xffff88001afd5e90, off=9, count=3072, eof=0xffff88001afd5e9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:137
+137     ) {
+(gdb) c
+Continuing.
+}}}