From: Greg Kroah-Hartman Date: Wed, 11 Mar 2015 14:39:04 +0000 (+0100) Subject: 3.10-stable patches X-Git-Tag: v3.10.72~40 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=df6c631915d2c9b09eb3da5e186879769cb4cce6;p=thirdparty%2Fkernel%2Fstable-queue.git 3.10-stable patches added patches: x86-asm-entry-64-remove-a-bogus-ret_from_fork-optimization.patch --- diff --git a/queue-3.10/series b/queue-3.10/series index a2a9e7c3680..95a66224309 100644 --- a/queue-3.10/series +++ b/queue-3.10/series @@ -20,3 +20,4 @@ mm-compaction-fix-wrong-order-check-in-compact_finished.patch mm-memory.c-actually-remap-enough-memory.patch target-check-for-lba-sectors-wrap-around-in-sbc_parse_cdb.patch pm-qos-remove-duplicate-call-to-pm_qos_update_target.patch +x86-asm-entry-64-remove-a-bogus-ret_from_fork-optimization.patch diff --git a/queue-3.10/x86-asm-entry-64-remove-a-bogus-ret_from_fork-optimization.patch b/queue-3.10/x86-asm-entry-64-remove-a-bogus-ret_from_fork-optimization.patch new file mode 100644 index 00000000000..f3f85cbc8b8 --- /dev/null +++ b/queue-3.10/x86-asm-entry-64-remove-a-bogus-ret_from_fork-optimization.patch @@ -0,0 +1,56 @@ +From 956421fbb74c3a6261903f3836c0740187cf038b Mon Sep 17 00:00:00 2001 +From: Andy Lutomirski +Date: Thu, 5 Mar 2015 01:09:44 +0100 +Subject: x86/asm/entry/64: Remove a bogus 'ret_from_fork' optimization + +From: Andy Lutomirski + +commit 956421fbb74c3a6261903f3836c0740187cf038b upstream. + +'ret_from_fork' checks TIF_IA32 to determine whether 'pt_regs' and +the related state make sense for 'ret_from_sys_call'. This is +entirely the wrong check. TS_COMPAT would make a little more +sense, but there's really no point in keeping this optimization +at all. + +This fixes a return to the wrong user CS if we came from int +0x80 in a 64-bit task. + +Signed-off-by: Andy Lutomirski +Cc: Borislav Petkov +Cc: Denys Vlasenko +Cc: H. Peter Anvin +Cc: Linus Torvalds +Cc: Oleg Nesterov +Cc: Thomas Gleixner +Link: http://lkml.kernel.org/r/4710be56d76ef994ddf59087aad98c000fbab9a4.1424989793.git.luto@amacapital.net +[ Backported from tip:x86/asm. ] +Signed-off-by: Ingo Molnar +Signed-off-by: Greg Kroah-Hartman + +--- + arch/x86/kernel/entry_64.S | 13 ++++++++----- + 1 file changed, 8 insertions(+), 5 deletions(-) + +--- a/arch/x86/kernel/entry_64.S ++++ b/arch/x86/kernel/entry_64.S +@@ -557,11 +557,14 @@ ENTRY(ret_from_fork) + testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread? + jz 1f + +- testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET +- jnz int_ret_from_sys_call +- +- RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET +- jmp ret_from_sys_call # go to the SYSRET fastpath ++ /* ++ * By the time we get here, we have no idea whether our pt_regs, ++ * ti flags, and ti status came from the 64-bit SYSCALL fast path, ++ * the slow path, or one of the ia32entry paths. ++ * Use int_ret_from_sys_call to return, since it can safely handle ++ * all of the above. ++ */ ++ jmp int_ret_from_sys_call + + 1: + subq $REST_SKIP, %rsp # leave space for volatiles