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| author | Yonghong Song <yhs@fb.com> | 2017-11-08 11:28:45 -0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-11-08 21:05:23 +0100 |
| commit | d0cd64b02aa854d68ce517cb7da1fe4e4fff2653 (patch) | |
| tree | 418bb9bd443c622bb0737a30860de5a883ef4d92 /arch/x86/kernel/idt.c | |
| parent | a743bbeef27b9176987ec0cb7f906ab0ab52d1da (diff) | |
| download | linux-d0cd64b02aa854d68ce517cb7da1fe4e4fff2653.tar.bz2 | |
x86/idt: Remove X86_TRAP_BP initialization in idt_setup_traps()
Commit b70543a0b2b6("x86/idt: Move regular trap init to tables") moves
regular trap init for each trap vector into a table based
initialization. It introduced the initialization for vector X86_TRAP_BP
which was not in the code which it replaced. This breaks uprobe
functionality for x86_32; the probed program segfaults instead of handling
the probe proper.
The reason for this is that TRAP_BP is set up as system interrupt gate
(DPL3) in the early IDT and then replaced by a regular interrupt gate
(DPL0) in idt_setup_traps(). The DPL0 restriction causes the int3 trap
to fail with a #GP resulting in a SIGSEGV of the probed program.
On 64bit this does not cause a problem because the IDT entry is replaced
with a system interrupt gate (DPL3) with interrupt stack afterwards.
Remove X86_TRAP_BP from the def_idts table which is used in
idt_setup_traps(). Remove a redundant entry for X86_TRAP_NMI in def_idts
while at it. Tested on both x86_64 and x86_32.
[ tglx: Amended changelog with a description of the root cause ]
Fixes: b70543a0b2b6("x86/idt: Move regular trap init to tables")
Reported-and-tested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: a.p.zijlstra@chello.nl
Cc: ast@fb.com
Cc: oleg@redhat.com
Cc: luto@kernel.org
Cc: kernel-team@fb.com
Link: https://lkml.kernel.org/r/20171108192845.552709-1-yhs@fb.com
Diffstat (limited to 'arch/x86/kernel/idt.c')
| -rw-r--r-- | arch/x86/kernel/idt.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 6107ee1cb8d5..014cb2fc47ff 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -92,8 +92,6 @@ static const __initdata struct idt_data def_idts[] = { INTG(X86_TRAP_DF, double_fault), #endif INTG(X86_TRAP_DB, debug), - INTG(X86_TRAP_NMI, nmi), - INTG(X86_TRAP_BP, int3), #ifdef CONFIG_X86_MCE INTG(X86_TRAP_MC, &machine_check), |