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| author |   Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com> | 2012-02-26 21:47:55 +0530 |
|---|---|---|
| committer |   H. Peter Anvin <hpa@zytor.com> | 2012-02-26 12:59:04 -0800 |
| commit | 42dfc43ee5999ac64284476ea0ac6c937587cf2b (patch) | |
| tree | 4527353aa4f9cfedc09142f2a9da418c90b618e5 /arch/x86/kernel/nmi_selftest.c | |
| parent | Linux 3.3-rc4 (diff) | |
| download | linux-dev-42dfc43ee5999ac64284476ea0ac6c937587cf2b.tar.xz linux-dev-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 <siddhesh.poyarekar@gmail.com>
Link: http://lkml.kernel.org/r/1330273075-2949-1-git-send-email-siddhesh.poyarekar@gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/nmi_selftest.c')
0 files changed, 0 insertions, 0 deletions