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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2010-04-09 13:43:00 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2010-04-09 13:43:02 +0200 |
| commit | 176b1803ce4690d0dd94e16f118dbd14af045034 (patch) | |
| tree | 92601341680bf89e42ed0073bd5086d16405356c /arch/s390 | |
| parent | [S390] sclp_async: potential buffer overflow (diff) | |
| download | linux-176b1803ce4690d0dd94e16f118dbd14af045034.tar.xz linux-176b1803ce4690d0dd94e16f118dbd14af045034.zip | |
[S390] fix io_return critical section cleanup
If a machine check interrupts the io interrupt handler on one of the
instructions between io_return and io_leave the critical section
cleanup code will move the return psw to io_work_loop. By doing that
the switch from the asynchronous interrupt stack to the process stack
is skipped. If e.g. TIF_NEED_RESCHED is set things break because
the scheduler is called with the asynchronous interrupts stack.
Moving the psw back to io_return instead fixes the problem.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kernel/entry.S | 8 | ||||
| -rw-r--r-- | arch/s390/kernel/entry64.S | 8 |
2 files changed, 14 insertions, 2 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 4348f9bc5393..6af7045280a8 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -964,7 +964,7 @@ cleanup_critical: clc 4(4,%r12),BASED(cleanup_table_io_work_loop) bl BASED(0f) clc 4(4,%r12),BASED(cleanup_table_io_work_loop+4) - bl BASED(cleanup_io_return) + bl BASED(cleanup_io_work_loop) 0: br %r14 @@ -1039,6 +1039,12 @@ cleanup_sysc_leave_insn: cleanup_io_return: mvc __LC_RETURN_PSW(4),0(%r12) + mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_io_return) + la %r12,__LC_RETURN_PSW + br %r14 + +cleanup_io_work_loop: + mvc __LC_RETURN_PSW(4),0(%r12) mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_io_work_loop) la %r12,__LC_RETURN_PSW br %r14 diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index 29fd0f1e6ec4..52106d53271c 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -946,7 +946,7 @@ cleanup_critical: clc 8(8,%r12),BASED(cleanup_table_io_work_loop) jl 0f clc 8(8,%r12),BASED(cleanup_table_io_work_loop+8) - jl cleanup_io_return + jl cleanup_io_work_loop 0: br %r14 @@ -1021,6 +1021,12 @@ cleanup_sysc_leave_insn: cleanup_io_return: mvc __LC_RETURN_PSW(8),0(%r12) + mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_return) + la %r12,__LC_RETURN_PSW + br %r14 + +cleanup_io_work_loop: + mvc __LC_RETURN_PSW(8),0(%r12) mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_work_loop) la %r12,__LC_RETURN_PSW br %r14 |