I looked at this whole day today, but found nothing.
The code analysis for usbmon shows nothing. Anyone wants to have
a look?
Reproduction does not work either. I tried various loads, loops
of opening/closing while pushing events from USB, nothing.
BTW, I tried to create memory pressure with mem=300MB, result:
top: page allocation failure. order:4, mode:0xc0d0
Pid: 2337, comm: top Not tainted 2.6.25-ub #33
Call Trace:
[<ffffffff8027450d>] __alloc_pages+0x32f/0x352
[<ffffffff80272252>] rmqueue_bulk+0x8a/0x9b
[<ffffffff80273a3d>] __get_free_pages+0xe/0x4d
[<ffffffff802ddd14>] show_stat+0x25/0x4f1
[<ffffffff80252f6f>] __lock_acquire+0xd95/0xda4
[<ffffffff80252f6f>] __lock_acquire+0xd95/0xda4
[<ffffffff802b349c>] seq_read+0x37/0x2a7
[<ffffffff80251a2a>] mark_held_locks+0x57/0x73
[<ffffffff802b349c>] seq_read+0x37/0x2a7
[<ffffffff80470fff>] mutex_lock_nested+0x23a/0x256
[<ffffffff80251bd4>] trace_hardirqs_on+0xf9/0x123
[<ffffffff8047100c>] mutex_lock_nested+0x247/0x256
[<ffffffff80470fff>] mutex_lock_nested+0x23a/0x256
[<ffffffff8047100c>] mutex_lock_nested+0x247/0x256
[<ffffffff802b3579>] seq_read+0x114/0x2a7
[<ffffffff802b3465>] seq_read+0x0/0x2a7
[<ffffffff802d74a7>] proc_reg_read+0x80/0x9b
The error is not just advisory, the application (top) dies because
/proc/stat cannot be read. I'm surprised that you people managed
to get the warning at 2443, because things start unravel way earlier
for me.
-- Pete
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