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authorFrédéric Weisbecker <fweisbec@gmail.com>2008-09-24 16:31:56 +0100
committerIngo Molnar <mingo@elte.hu>2008-10-14 10:38:16 +0200
commitac2b86fdef5b44f194eefaa6b7b6aea9423d1bc2 (patch)
tree7ca5225be1cd41e328a54158e1c4cfaaefc1b9e4 /arch
parent37a52f5ef120b93734bb2461744512b55695f69c (diff)
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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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/ftrace.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 66d900248fc2..222507e8157b 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -71,13 +71,13 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
* No real locking needed, this code is run through
* kstop_machine, or before SMP starts.
*/
- if (__copy_from_user(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
+ if (__copy_from_user_inatomic(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
return 1;
if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
return 2;
- WARN_ON_ONCE(__copy_to_user((char __user *)ip, new_code,
+ WARN_ON_ONCE(__copy_to_user_inatomic((char __user *)ip, new_code,
MCOUNT_INSN_SIZE));
sync_core();