<div dir="ltr"><span style="font-family:arial,sans-serif;font-size:13px">Hi,</span><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">I am testing kgdb on freescale p2020 target.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">In target<br>------------</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div>
<div style="font-family:arial,sans-serif;font-size:13px">1) </div><div style="font-family:arial,sans-serif;font-size:13px">root@freescale-p2020ds:~# uname -a</div><div style="font-family:arial,sans-serif;font-size:13px">Linux freescale-p2020ds 3.10.20-rt14+ #9 SMP Thu Jan 16 16:32:15 IST 2014 ppc GNU/Linux</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">2)</div><div style="font-family:arial,sans-serif;font-size:13px">root@freescale-p2020ds:~# cat /proc/cpuinfo </div>
<div style="font-family:arial,sans-serif;font-size:13px">processor : 0</div><div style="font-family:arial,sans-serif;font-size:13px">cpu : e500v2</div><div style="font-family:arial,sans-serif;font-size:13px">
clock : 999.990008MHz</div><div style="font-family:arial,sans-serif;font-size:13px">revision : 4.0 (pvr 8021 1040)</div><div style="font-family:arial,sans-serif;font-size:13px">bogomips : 124.99</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">processor : 1</div><div style="font-family:arial,sans-serif;font-size:13px">cpu : e500v2</div>
<div style="font-family:arial,sans-serif;font-size:13px">clock : 999.990008MHz</div><div style="font-family:arial,sans-serif;font-size:13px">revision : 4.0 (pvr 8021 1040)</div><div style="font-family:arial,sans-serif;font-size:13px">
bogomips : 124.99</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">total bogomips : 249.99</div><div style="font-family:arial,sans-serif;font-size:13px">
timebase : 62499376</div><div style="font-family:arial,sans-serif;font-size:13px">platform : P2020 DS</div><div style="font-family:arial,sans-serif;font-size:13px">model : fsl,P2020DS</div><div style="font-family:arial,sans-serif;font-size:13px">
Memory : 768 MB</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">3)</div><div style="font-family:arial,sans-serif;font-size:13px">freescale-p2020ds:~# echo "ttyS1,115200" > /sys/module/kgdboc/parameters/kgdoc</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">4) I set up host (settings given below); Then I send "SysRq : DEBUG"</div><div style="font-family:arial,sans-serif;font-size:13px">
<br></div><div style="font-family:arial,sans-serif;font-size:13px">In host</div><div style="font-family:arial,sans-serif;font-size:13px">----------</div><div style="font-family:arial,sans-serif;font-size:13px"><div>(gdb) target remote /dev/ttyS0</div>
<div>Remote debugging using /dev/ttyS0</div><div>kgdb_breakpoint () at kernel/debug/debug_core.c:1013</div><div>1013<span style="white-space:pre-wrap"> </span>arch_kgdb_breakpoint();</div><div>(gdb) b sys_sync</div><div>
Breakpoint 1 at 0xc0167288: file fs/sync.c, line 103.</div><div>(gdb) c</div><div>Continuing.</div></div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">
I am able to take control in host; after that I am setting breakpoint at "sys_sync"</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">
In target</div><div style="font-family:arial,sans-serif;font-size:13px">------------</div><div style="font-family:arial,sans-serif;font-size:13px">root@freescale-p2020ds:~# for i in 1 2 3 4 5 6 7 8 9</div><div style="font-family:arial,sans-serif;font-size:13px">
> do</div><div style="font-family:arial,sans-serif;font-size:13px">> sync</div><div style="font-family:arial,sans-serif;font-size:13px">> done</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div>
<div style="font-family:arial,sans-serif;font-size:13px">In host</div><div style="font-family:arial,sans-serif;font-size:13px">----------</div><div style="font-family:arial,sans-serif;font-size:13px"><div>Breakpoint 1, sys_sync () at fs/sync.c:103</div>
<div>103<span style="white-space:pre-wrap"> </span>{</div><div>(gdb) c</div><div>Continuing.</div></div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">
Breakpoint is hit only one time instead of 9 times; after that target hangs.</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">Then i tried to send "SysRq : DEBUG" in target kernel panics.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">I have pasted the panic below.</div><div style="font-family:arial,sans-serif;font-size:13px"><br>
</div><div style="font-family:arial,sans-serif;font-size:13px">#########################################</div><div style="font-family:arial,sans-serif;font-size:13px"><div>SysRq : DEBUG</div><div>Kernel panic - not syncing: Recursive entry to debugger</div>
<div>CPU: 1 PID: 2266 Comm: cron Not tainted 3.10.20-rt14+ #6</div><div>Call Trace:</div><div>[effe5d10] [c0008060] show_stack+0x4c/0x168 (unreliable)</div><div>[effe5d50] [c0588878] panic+0xe4/0x224</div><div>[effe5da0] [c00b2cbc] kgdb_handle_exception+0x1d4/0x1f8</div>
<div>[effe5df0] [c0010038] kgdb_handle_breakpoint+0x4c/0x80</div><div>[effe5e00] [c057e7e0] program_check_exception+0x10c/0x264</div><div>[effe5e10] [c000f660] ret_from_except_full+0x0/0x4c</div><div>--- Exception: 700 at sysrq_handle_dbg+0x3c/0xc8</div>
<div> LR = __handle_sysrq+0x154/0x1cc</div><div>[effe5ed0] [c033df5c] __handle_sysrq+0x140/0x1cc (unreliable)</div><div>[effe5f00] [c0353ef8] serial8250_rx_chars+0xe8/0x218</div><div>[effe5f30] [c0359644] fsl8250_handle_irq+0xac/0x174</div>
<div>[effe5f50] [c0352f9c] serial8250_interrupt+0x40/0xe8</div><div>[effe5f70] [c00b5500] handle_irq_event_percpu+0xcc/0x2a8</div><div>[effe5fc0] [c00b5720] handle_irq_event+0x44/0x74</div><div>[effe5fe0] [c00b8e14] handle_fasteoi_irq+0xd0/0x17c</div>
<div>[effe5ff0] [c000d58c] call_handle_irq+0x18/0x28</div><div>[c4f91b10] [c0004f60] do_IRQ+0x150/0x224</div><div>[c4f91b40] [c000f6ac] ret_from_except+0x0/0x18</div><div>--- Exception: 501 at rpcauth_lookup_credcache+0x138/0x2a4</div>
<div> LR = rpcauth_lookup_credcache+0xb8/0x2a4</div><div>[c4f91c00] [24002424] 0x24002424 (unreliable)</div><div>[c4f91c50] [c055cb84] rpcauth_lookupcred+0x64/0xac</div><div>[c4f91c80] [c055ce2c] rpcauth_refreshcred+0x11c/0x124</div>
<div>[c4f91cc0] [c055ac80] __rpc_execute+0x8c/0x330</div><div>[c4f91d10] [c05540b8] rpc_run_task+0x9c/0xc4</div><div>[c4f91d20] [c0554204] rpc_call_sync+0x50/0xb8</div><div>[c4f91d50] [c0257164] nfs_proc_getattr+0x48/0x5c</div>
<div>[c4f91d70] [c024aaa4] __nfs_revalidate_inode+0xa8/0x168</div><div>[c4f91d90] [c024ac1c] nfs_revalidate_mapping+0xb8/0x194</div><div>[c4f91da0] [c0251f00] nfs_follow_link+0x24/0xc8</div><div>[c4f91dc0] [c0145280] path_lookupat+0x2f4/0x824</div>
<div>[c4f91e10] [c01457dc] filename_lookup.isra.33+0x2c/0x8c</div><div>[c4f91e30] [c0147a74] user_path_at_empty+0x58/0x9c</div><div>[c4f91eb0] [c013d5bc] vfs_fstatat+0x54/0xb4</div><div>[c4f91ee0] [c013d93c] SyS_stat64+0x1c/0x44</div>
<div>[c4f91f40] [c000eec0] ret_from_syscall+0x0/0x3c</div><div>--- Exception: c01 at 0xff08a98</div><div> LR = 0xfed53e8</div></div><div style="font-family:arial,sans-serif;font-size:13px"><div>CPU: 1 PID: 2266 Comm: cron Not tainted 3.10.20-rt14+ #6</div>
<div>Call Trace:</div><div>[effe5bb0] [c0008060] show_stack+0x4c/0x168 (unreliable)</div><div>[effe5bf0] [c00b2cac] kgdb_handle_exception+0x1c4/0x1f8</div><div>[effe5c40] [c0010038] kgdb_handle_breakpoint+0x4c/0x80</div><div>
[effe5c50] [c057e7e0] program_check_exception+0x10c/0x264</div><div>[effe5c60] [c000f660] ret_from_except_full+0x0/0x4c</div><div>--- Exception: 700 at kgdb_panic_event+0x1c/0x3c</div><div> LR = notifier_call_chain+0x60/0xb0</div>
<div>[effe5d20] [00000000] (nil) (unreliable)</div><div>[effe5d40] [c05819dc] __atomic_notifier_call_chain+0x14/0x24</div><div>[effe5d50] [c05888a8] panic+0x114/0x224</div><div>[effe5da0] [c00b2cbc] kgdb_handle_exception+0x1d4/0x1f8</div>
<div>[effe5df0] [c0010038] kgdb_handle_breakpoint+0x4c/0x80</div><div>[effe5e00] [c057e7e0] program_check_exception+0x10c/0x264</div><div>[effe5e10] [c000f660] ret_from_except_full+0x0/0x4c</div><div>--- Exception: 700 at sysrq_handle_dbg+0x3c/0xc8</div>
<div> LR = __handle_sysrq+0x154/0x1cc</div><div>[effe5ed0] [c033df5c] __handle_sysrq+0x140/0x1cc (unreliable)</div><div>[effe5f00] [c0353ef8] serial8250_rx_chars+0xe8/0x218</div><div>[effe5f30] [c0359644] fsl8250_handle_irq+0xac/0x174</div>
<div>[effe5f50] [c0352f9c] serial8250_interrupt+0x40/0xe8</div><div>[effe5f70] [c00b5500] handle_irq_event_percpu+0xcc/0x2a8</div><div>[effe5fc0] [c00b5720] handle_irq_event+0x44/0x74</div><div>[effe5fe0] [c00b8e14] handle_fasteoi_irq+0xd0/0x17c</div>
<div>[effe5ff0] [c000d58c] call_handle_irq+0x18/0x28</div><div>[c4f91b10] [c0004f60] do_IRQ+0x150/0x224</div><div>[c4f91b40] [c000f6ac] ret_from_except+0x0/0x18</div><div>--- Exception: 501 at rpcauth_lookup_credcache+0x138/0x2a4</div>
<div> LR = rpcauth_lookup_credcache+0xb8/0x2a4</div><div>[c4f91c00] [24002424] 0x24002424 (unreliable)</div><div>[c4f91c50] [c055cb84] rpcauth_lookupcred+0x64/0xac</div><div>[c4f91c80] [c055ce2c] rpcauth_refreshcred+0x11c/0x124</div>
<div>[c4f91cc0] [c055ac80] __rpc_execute+0x8c/0x330</div><div>[c4f91d10] [c05540b8] rpc_run_task+0x9c/0xc4</div><div>[c4f91d20] [c0554204] rpc_call_sync+0x50/0xb8</div><div>[c4f91d50] [c0257164] nfs_proc_getattr+0x48/0x5c</div>
<div>[c4f91d70] [c024aaa4] __nfs_revalidate_inode+0xa8/0x168</div><div>[c4f91d90] [c024ac1c] nfs_revalidate_mapping+0xb8/0x194</div><div>[c4f91da0] [c0251f00] nfs_follow_link+0x24/0xc8</div><div>[c4f91dc0] [c0145280] path_lookupat+0x2f4/0x824</div>
<div>[c4f91e10] [c01457dc] filename_lookup.isra.33+0x2c/0x8c</div><div>[c4f91e30] [c0147a74] user_path_at_empty+0x58/0x9c</div><div>[c4f91eb0] [c013d5bc] vfs_fstatat+0x54/0xb4</div><div>[c4f91ee0] [c013d93c] SyS_stat64+0x1c/0x44</div>
<div>[c4f91f40] [c000eec0] ret_from_syscall+0x0/0x3c</div><div>--- Exception: c01 at 0xff08a98</div><div> LR = 0xfed53e8</div></div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">
<br></div><div style="font-family:arial,sans-serif;font-size:13px">########################################################</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">
Could you please share your thoughts on this issue?</div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">I have also attached my kernel .config.</div>
<div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">Regards,</div><div style="font-family:arial,sans-serif;font-size:13px">Arun C</div></div>