-stable review patch. If anyone has any objections, please let us know. ------------------
From: Jeff Dike <[EMAIL PROTECTED]>, Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> Revert the following patch, because of miscompilation problems in different environments leading to UML not working *at all* in TT mode; it was merged lately in 2.6 development cycle, a little after being written, and has caused problems to lots of people; I know it's a bit too long, but it shouldn't have been merged in first place, so I still apply for inclusion in the -stable tree. Anyone using this feature currently is either using some older kernel (some reports even used 2.6.12-rc4-mm2) or using this patch, as included in my -bs patchset. For now there's not yet a fix for this patch, so for now the best thing is to drop it (which was widely reported to give a working kernel). "Convert the boot-time host ptrace testing from clone to fork. They were essentially doing fork anyway. This cleans up the code a bit, and makes valgrind a bit happier about grinding it." URL: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=98fdffccea6cc3fe9dba32c0fcc310bcb5d71529 Signed-off-by: Jeff Dike <[EMAIL PROTECTED]> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> Signed-off-by: Chris Wright <[EMAIL PROTECTED]> Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]> --- arch/um/kernel/process.c | 48 ++++++++++++++++++++++++++++------------------- 1 files changed, 29 insertions(+), 19 deletions(-) --- linux-2.6.12.2.orig/arch/um/kernel/process.c 2005-06-17 12:48:29.000000000 -0700 +++ linux-2.6.12.2/arch/um/kernel/process.c 2005-07-13 10:56:41.000000000 -0700 @@ -130,7 +130,7 @@ return(arg.pid); } -static int ptrace_child(void) +static int ptrace_child(void *arg) { int ret; int pid = os_getpid(), ppid = getppid(); @@ -159,16 +159,20 @@ _exit(ret); } -static int start_ptraced_child(void) +static int start_ptraced_child(void **stack_out) { + void *stack; + unsigned long sp; int pid, n, status; - pid = fork(); - if(pid == 0) - ptrace_child(); - + stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if(stack == MAP_FAILED) + panic("check_ptrace : mmap failed, errno = %d", errno); + sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); + pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL); if(pid < 0) - panic("check_ptrace : fork failed, errno = %d", errno); + panic("check_ptrace : clone failed, errno = %d", errno); CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); if(n < 0) panic("check_ptrace : wait failed, errno = %d", errno); @@ -176,6 +180,7 @@ panic("check_ptrace : expected SIGSTOP, got status = %d", status); + *stack_out = stack; return(pid); } @@ -183,12 +188,12 @@ * just avoid using sysemu, not panic, but only if SYSEMU features are broken. * So only for SYSEMU features we test mustpanic, while normal host features * must work anyway!*/ -static int stop_ptraced_child(int pid, int exitcode, int mustexit) +static int stop_ptraced_child(int pid, void *stack, int exitcode, int mustpanic) { int status, n, ret = 0; if(ptrace(PTRACE_CONT, pid, 0, 0) < 0) - panic("stop_ptraced_child : ptrace failed, errno = %d", errno); + panic("check_ptrace : ptrace failed, errno = %d", errno); CATCH_EINTR(n = waitpid(pid, &status, 0)); if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) { int exit_with = WEXITSTATUS(status); @@ -199,13 +204,15 @@ printk("check_ptrace : child exited with exitcode %d, while " "expecting %d; status 0x%x", exit_with, exitcode, status); - if (mustexit) + if (mustpanic) panic("\n"); else printk("\n"); ret = -1; } + if(munmap(stack, PAGE_SIZE) < 0) + panic("check_ptrace : munmap failed, errno = %d", errno); return ret; } @@ -227,11 +234,12 @@ static void __init check_sysemu(void) { + void *stack; int pid, syscall, n, status, count=0; printk("Checking syscall emulation patch for ptrace..."); sysemu_supported = 0; - pid = start_ptraced_child(); + pid = start_ptraced_child(&stack); if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) goto fail; @@ -249,7 +257,7 @@ panic("check_sysemu : failed to modify system " "call return, errno = %d", errno); - if (stop_ptraced_child(pid, 0, 0) < 0) + if (stop_ptraced_child(pid, stack, 0, 0) < 0) goto fail_stopped; sysemu_supported = 1; @@ -257,7 +265,7 @@ set_using_sysemu(!force_sysemu_disabled); printk("Checking advanced syscall emulation patch for ptrace..."); - pid = start_ptraced_child(); + pid = start_ptraced_child(&stack); while(1){ count++; if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0) @@ -282,7 +290,7 @@ break; } } - if (stop_ptraced_child(pid, 0, 0) < 0) + if (stop_ptraced_child(pid, stack, 0, 0) < 0) goto fail_stopped; sysemu_supported = 2; @@ -293,17 +301,18 @@ return; fail: - stop_ptraced_child(pid, 1, 0); + stop_ptraced_child(pid, stack, 1, 0); fail_stopped: printk("missing\n"); } void __init check_ptrace(void) { + void *stack; int pid, syscall, n, status; printk("Checking that ptrace can change system call numbers..."); - pid = start_ptraced_child(); + pid = start_ptraced_child(&stack); if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0) panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno); @@ -330,7 +339,7 @@ break; } } - stop_ptraced_child(pid, 0, 1); + stop_ptraced_child(pid, stack, 0, 1); printk("OK\n"); check_sysemu(); } @@ -362,10 +371,11 @@ static inline int check_skas3_ptrace_support(void) { struct ptrace_faultinfo fi; + void *stack; int pid, n, ret = 1; printf("Checking for the skas3 patch in the host..."); - pid = start_ptraced_child(); + pid = start_ptraced_child(&stack); n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); if (n < 0) { @@ -380,7 +390,7 @@ } init_registers(pid); - stop_ptraced_child(pid, 1, 1); + stop_ptraced_child(pid, stack, 1, 1); return(ret); } ------------------------------------------------------- This SF.Net email is sponsored by the 'Do More With Dual!' webinar happening July 14 at 8am PDT/11am EDT. 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