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| author | Siddhesh Poyarekar <[email protected]> | 2012-02-26 16:17:55 +0000 |
|---|---|---|
| committer | H. Peter Anvin <[email protected]> | 2012-02-26 20:59:04 +0000 |
| commit | 42dfc43ee5999ac64284476ea0ac6c937587cf2b (patch) | |
| tree | 4527353aa4f9cfedc09142f2a9da418c90b618e5 /lib/string_helpers.c | |
| parent | Linux 3.3-rc4 (diff) | |
| download | kernel-42dfc43ee5999ac64284476ea0ac6c937587cf2b.tar.gz kernel-42dfc43ee5999ac64284476ea0ac6c937587cf2b.zip | |
x86_64: Record stack pointer before task execution begins
task->thread.usersp is unusable immediately after a binary is exec()'d
until it undergoes a context switch cycle. The start_thread() function
called during execve() saves the stack pointer into pt_regs and into
old_rsp, but fails to record it into task->thread.usersp.
Because of this, KSTK_ESP(task) returns an incorrect value for a
64-bit program until the task is switched out and back in since
switch_to swaps %rsp values in and out into task->thread.usersp.
Signed-off-by: Siddhesh Poyarekar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
Diffstat (limited to 'lib/string_helpers.c')
0 files changed, 0 insertions, 0 deletions