ftrace faulted on writing

From: Jack Steiner
Date: Fri Feb 19 2010 - 17:36:50 EST


Is this a known problem???

This is from a 2.6.32 distro beta kernel running on a nehalem processor (SGI UV system):


Feb 19 10:30:49 uv17-sys kernel: [ 157.477841] WARNING: at kernel/trace/ftrace.c:1007 ftrace_bug+0x264/0x2a0()
Feb 19 10:30:49 uv17-sys kernel: [ 157.477844] Hardware name: Stoutland Platform
Feb 19 10:30:49 uv17-sys kernel: [ 157.477846] Modules linked in: autofs4 binfmt_misc microcode fuse dm_mod
pcspkr iTCO_wdt sg ioatdma iTCO_vendor_support button i2c_i801 dca
Feb 19 10:30:49 uv17-sys kernel: [ 157.477861] Pid: 12438, comm: kstop/0 Not tainted 2.6.32.7-jfs-static-sles11-sp1 #11
Feb 19 10:30:49 uv17-sys kernel: [ 157.477866] Call Trace:
Feb 19 10:30:49 uv17-sys kernel: [ 157.477874] [<ffffffff810bed94>] ? ftrace_bug+0x264/0x2a0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477885] [<ffffffff81055410>] warn_slowpath_common+0x80/0xd0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477904] [<ffffffff810001a4>] ? _stext+0xc/0x18
Feb 19 10:30:49 uv17-sys kernel: [ 157.477908] [<ffffffff81055474>] warn_slowpath_null+0x14/0x20
Feb 19 10:30:49 uv17-sys kernel: [ 157.477912] [<ffffffff810bed94>] ftrace_bug+0x264/0x2a0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477917] [<ffffffff810bef10>] ftrace_replace_code+0x140/0x1b0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477929] [<ffffffff810a48b0>] ? stop_cpu+0x0/0x100
Feb 19 10:30:49 uv17-sys kernel: [ 157.477933] [<ffffffff810bf00a>] __ftrace_modify_code+0x8a/0x90
Feb 19 10:30:49 uv17-sys kernel: [ 157.477938] [<ffffffff810a4959>] stop_cpu+0xa9/0x100
Feb 19 10:30:49 uv17-sys kernel: [ 157.477950] [<ffffffff8106ef43>] worker_thread+0x183/0x260
Feb 19 10:30:49 uv17-sys kernel: [ 157.477958] [<ffffffff81073900>] ? autoremove_wake_function+0x0/0x40
Feb 19 10:30:49 uv17-sys kernel: [ 157.477963] [<ffffffff8106edc0>] ? worker_thread+0x0/0x260
Feb 19 10:30:49 uv17-sys kernel: [ 157.477967] [<ffffffff81073546>] kthread+0x96/0xb0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477973] [<ffffffff8100407a>] child_rip+0xa/0x20
Feb 19 10:30:49 uv17-sys kernel: [ 157.477977] [<ffffffff810734b0>] ? kthread+0x0/0xb0
Feb 19 10:30:49 uv17-sys kernel: [ 157.477981] [<ffffffff81004070>] ? child_rip+0x0/0x20
Feb 19 10:30:49 uv17-sys kernel: [ 157.477985] ---[ end trace 3058770ec83b6e0e ]---
Feb 19 10:30:49 uv17-sys kernel: [ 157.477988] ftrace faulted on writing [<ffffffff810001a4>] _stext+0xc/0x18

It occurs right after:
# export DB="/sys/kernel/debug/tracing"
# echo 1 >/proc/sys/kernel/ftrace_enabled
# echo function > $DB/current_tracer


--- jack
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