linux-stable-rt/arch/x86
Frédéric Weisbecker ac2b86fdef x86/ftrace: use uaccess in atomic context
With latest -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"

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:16 +02:00
..
boot Merge branches 'x86/xen', 'x86/build', 'x86/microcode', 'x86/mm-debug-v2', 'x86/memory-corruption-check', 'x86/early-printk', 'x86/xsave', 'x86/ptrace-v2', 'x86/quirks', 'x86/setup', 'x86/spinlocks' and 'x86/signal' into x86/core-v2 2008-10-12 15:50:02 +02:00
configs x86: merge winchip-2 and winchip-2a cpu choices 2008-10-13 10:22:48 +02:00
crypto
ia32 x86-64: slightly stream-line 32-bit syscall entry code 2008-10-13 10:19:54 +02:00
kernel x86/ftrace: use uaccess in atomic context 2008-10-14 10:38:16 +02:00
kvm Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D 2008-10-11 20:23:20 +02:00
lguest
lib Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D 2008-10-11 20:23:20 +02:00
mach-default
mach-generic x86: check dsdt before find oem table for es7000, v2 2008-10-13 10:21:07 +02:00
mach-rdc321x
mach-voyager
math-emu
mm mmiotrace: remove left-over marker cruft 2008-10-14 10:37:17 +02:00
oprofile Merge branch 'linus' into oprofile-v2 2008-10-13 11:05:51 +02:00
pci Merge branches 'oprofile-v2' and 'timers/hpet' into x86/core-v4 2008-10-13 14:18:42 +02:00
power Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D 2008-10-11 20:23:20 +02:00
vdso
video
xen Merge branch 'linus' into x86/xen 2008-10-12 12:37:32 +02:00
Kconfig ftrace: enable using mcount recording on x86 2008-10-14 10:34:54 +02:00
Kconfig.cpu x86: adjust dependencies for CONFIG_X86_CMOV 2008-10-13 10:33:50 +02:00
Kconfig.debug
Makefile
Makefile_32.cpu x86: merge winchip-2 and winchip-2a cpu choices 2008-10-13 10:22:48 +02:00