Messages in this thread | | | Date | Wed, 24 Sep 2008 10:31:28 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [Patch -tip] x86/ftrace: use uaccess in atomic context |
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On Wed, 24 Sep 2008, Fr?d?ric Weisbecker wrote:
> Hello, > > With last -tip I get this bug: > > [ 49.439988] in_atomic():0, irqs_disabled():1 > [ 49.440118] INFO: lockdep is turned off. > [ 49.440118] Pid: 2814, comm: modprobe Tainted: G W 2.6.27-rc7 #4 > [ 49.440118] [<c01215e1>] __might_sleep+0xe1/0x120 > [ 49.440118] [<c01148ea>] ftrace_modify_code+0x2a/0xd0 > [ 49.440118] [<c01148a2>] ? ftrace_test_p6nop+0x0/0xa > [ 49.440118] [<c016e80e>] __ftrace_update_code+0xfe/0x2f0 > [ 49.440118] [<c01148a2>] ? ftrace_test_p6nop+0x0/0xa > [ 49.440118] [<c016f190>] ftrace_convert_nops+0x50/0x80 > [ 49.440118] [<c016f1d6>] ftrace_init_module+0x16/0x20 > [ 49.440118] [<c015498b>] load_module+0x185b/0x1d30 > [ 49.440118] [<c01767a0>] ? find_get_page+0x0/0xf0 > [ 49.440118] [<c02463c0>] ? sprintf+0x0/0x30 > [ 49.440118] [<c034e012>] ? mutex_lock_interruptible_nested+0x1f2/0x350 > [ 49.440118] [<c0154eb3>] sys_init_module+0x53/0x1b0 > [ 49.440118] [<c0352340>] ? do_page_fault+0x0/0x740 > [ 49.440118] [<c0104012>] syscall_call+0x7/0xb > [ 49.440118] ======================= > > It is because ftrace_modify_code() calls copy_to_user and > copy_from_user. > These functions have been inserted after guessing that there > couldn't be any race condition but copy_[to/from]_user might > sleep and __ftrace_update_code is called with local_irq_saved. > > These function have been inserted since this commit: > d5e92e8978fd2574e415dc2792c5eb592978243d: > "ftrace: x86 use copy from user function" > > Following is a patch which correct it. > --- > Adapt uaccess functions's use to atomic context in ftrace_modify_code() > since we are in IRQ-off context: __ftrace_update_code() calls > local_irq_save(). > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > ---
I had this exact patch sitting it my quilt queue. I thought I sent it out, but it must have been lost in the noise.
Thanks,
Acked-by: Steven Rostedt <srostedt@redhat.com>
-- Steve
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