Re: [uml-devel] trinity commit 23dc478aba breaks syscall "mremap" at a 32 bit user mode linux
Richard Weinberger <[email protected]> Fri, 02 May 2014 09:46:44 +0200
| Newsgroups | org.kernel.vger.trinity,org.infradead.lists.linux-um |
|---|---|
| Message-ID | <[email protected]> |
Am 01.05.2014 23:34, schrieb Toralf Förster: > On 05/01/2014 10:57 PM, Richard Weinberger wrote: >> Toralf, >> >> Yeah, this is because trinity destroys the UML stub code. >> Please test the attached patch, it should fix the root cause of the problem. >> >> Thanks, >> //richard >> > > If I do just apply fix2.patch onto latest git tree v3.15-rc3-113-gba6728f then I do get after a while : > > * Starting sshd ... [ ok ] > * Starting local > net.core.warnings = 0 [ ok ] > Kernel panic - not syncing: do_syscall_stub : PTRACE_SETREGS failed, errno = 3 > > CPU: 0 PID: 1728 Comm: trinity-c0 Not tainted 3.15.0-rc3-00113-gba6728f-dirty #5 > Stack: > BUG: soft lockup - CPU#0 stuck for 22s! [trinity-c0:1728] > > EIP: c500:[<47c6cf00>] CPU: 0 Not tainted EFLAGS: 476af700 > Not tainted > EAX: 47cfc500 EBX: 0a024d00 ECX: 086c75fc EDX: 080fff88 > ESI: 0839f4bc EDI: 47cfc500 EBP: 0839f4bc DS: c500 ES: cd62 > EXT4-fs (ubda): error count: 1 > EXT4-fs (ubda): initial error at 1398962134: ext4_mb_generate_buddy:756 > EXT4-fs (ubda): last error at 1398962134: ext4_mb_generate_buddy:756 > > > which is a big improvement because before it crashes immediately after few seconds. > > After applying both fixes the test case runs w/o a crash till now. Can you please also try fix3 (without fix1/2)? I think I've found the other hidden issue. So far trinity did not crash my kernel... Thanks, //richard
fix3.patch
(text/x-patch, 1.9 KB)
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 9472079..f1b3eb1 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -12,6 +12,7 @@
#include <mem_user.h>
#include <os.h>
#include <skas.h>
+#include <kern_util.h>
struct host_vm_change {
struct host_vm_op {
@@ -124,6 +125,9 @@ static int add_munmap(unsigned long addr, unsigned long len,
struct host_vm_op *last;
int ret = 0;
+ if ((addr >= STUB_START) && (addr < STUB_END))
+ return -EINVAL;
+
if (hvc->index != 0) {
last = &hvc->ops[hvc->index - 1];
if ((last->type == MUNMAP) &&
@@ -283,8 +287,11 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
/* This is not an else because ret is modified above */
if (ret) {
printk(KERN_ERR "fix_range_common: failed, killing current "
- "process\n");
+ "process: %d\n", task_tgid_vnr(current));
+ /* We are under mmap_sem, release it such that current can terminate */
+ up_write(¤t->mm->mmap_sem);
force_sig(SIGKILL, current);
+ do_signal();
}
}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index d531879..908579f 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -54,7 +54,7 @@ static int ptrace_dump_regs(int pid)
void wait_stub_done(int pid)
{
- int n, status, err, bad_stop = 0;
+ int n, status, err;
while (1) {
CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
@@ -74,8 +74,6 @@ void wait_stub_done(int pid)
if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
return;
- else
- bad_stop = 1;
bad_wait:
err = ptrace_dump_regs(pid);
@@ -85,10 +83,7 @@ bad_wait:
printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
"pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
status);
- if (bad_stop)
- kill(pid, SIGKILL);
- else
- fatal_sigsegv();
+ fatal_sigsegv();
}
extern unsigned long current_stub_stack(void);