Comment 4 for bug 346303

Oh yes, I am going to change kernel code because your tool scared your users senseless for a LOG_WARN message. Forget it.

LOG_WARN is of LOWER severity than KERN_ERR, which is also somewhat common, and in no way means the kernel is unstable. At most it means a driver encountered an error condition that the user should know about.

We have KERN_CRIT, KERN_ALERT and KERN_EMERG for the situations where something really bad is about to happen, and WARN_ON() and BUG_ON() for kernel bugs or other really strange situations that should be notified to the kernel people.

It gets even more strange to see this kind of answer in a bug (#430361) that was ultimately caused by some utterly broken tool that touches sysfs files at random. Instead of people scrambling out to find out why something they are about to ship is reading files in sysfs at random, I get asked to change a kernel driver log message so that it won't trip a (broken) regexp that thinks anything that start with "WARNING" is the result of WARN_ON?!

Compare THIS:
------------[ cut here ]------------
WARNING: at drivers/platform/x86/thinkpad_acpi.c:3759 hotkey_enabledisable_warn+0x50/0x65 [thinkpad_acpi]()
Hardware name: 2687DDU
thinkpad_acpi: hotkey enable/disable functionality has been removed from the driver. Hotkeys are always enabled
Modules linked in: thinkpad_acpi ppp_deflate bsd_comp ppp_async crc_ccitt ppp_generic slhc option usbserial usb_storage radeon drm i2c_core tp_smapi thinkpad_ec snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm rfkill snd_seq_dummy ipw2200 libipw video output snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq tg3 libphy snd_timer snd_seq_device snd soundcore snd_page_alloc ehci_hcd uhci_hcd joydev [last unloaded: thinkpad_acpi]
Pid: 12451, comm: bash Not tainted 2.6.31.6-t43 #1
Call Trace:
 [<c1021119>] warn_slowpath_common+0x60/0x90
 [<c102117d>] warn_slowpath_fmt+0x24/0x27
 [<fa969431>] hotkey_enabledisable_warn+0x50/0x65 [thinkpad_acpi]
 [<fa9694d3>] hotkey_write+0x8d/0x164 [thinkpad_acpi]
 [<fa969980>] dispatch_procfs_write+0x71/0x91 [thinkpad_acpi]
 [<c10a54d3>] proc_file_write+0x6b/0x86
 [<c10a5468>] ? proc_file_write+0x0/0x86
 [<c10a1cbd>] proc_reg_write+0x81/0x95
 [<c10a1c3c>] ? proc_reg_write+0x0/0x95
 [<c10707ee>] vfs_write+0x8a/0x113
 [<c1070910>] sys_write+0x3b/0x60
 [<c10028f0>] sysenter_do_call+0x12/0x22
---[ end trace 7534b65473f2e981 ]---

to THIS:
thinkpad_acpi: WARNING: sysfs attribute hotkey_enable is deprecated and will be removed. Hotkeys can be disabled through hotkey_mask

That "cut here" and "end trace" lines are not there for show.