diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/basic/process-util.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/src/basic/process-util.c b/src/basic/process-util.c index 77d76958c..366aabba8 100644 --- a/src/basic/process-util.c +++ b/src/basic/process-util.c @@ -336,15 +336,33 @@ int rename_process(const char name[]) { /* Now, let's tell the kernel about this new memory */ if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0) { - log_debug_errno(errno, "PR_SET_MM_ARG_START failed, proceeding without: %m"); - (void) munmap(nn, nn_size); - goto use_saved_argv; - } + /* HACK: prctl() API is kind of dumb on this point. The existing end address may already be + * below the desired start address, in which case the kernel may have kicked this back due + * to a range-check failure (see linux/kernel/sys.c:validate_prctl_map() to see this in + * action). The proper solution would be to have a prctl() API that could set both start+end + * simultaneously, or at least let us query the existing address to anticipate this condition + * and respond accordingly. For now, we can only guess at the cause of this failure and try + * a workaround--which will briefly expand the arg space to something potentially huge before + * resizing it to what we want. */ + log_debug_errno(errno, "PR_SET_MM_ARG_START failed, attempting PR_SET_MM_ARG_END hack: %m"); + + if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0) { + log_debug_errno(errno, "PR_SET_MM_ARG_END hack failed, proceeding without: %m"); + (void) munmap(nn, nn_size); + goto use_saved_argv; + } - /* And update the end pointer to the new end, too. If this fails, we don't really know what to do, it's - * pretty unlikely that we can rollback, hence we'll just accept the failure, and continue. */ - if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0) - log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m"); + if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0) { + log_debug_errno(errno, "PR_SET_MM_ARG_START still failed, proceeding without: %m"); + goto use_saved_argv; + } + } else { + /* And update the end pointer to the new end, too. If this fails, we don't really know what + * to do, it's pretty unlikely that we can rollback, hence we'll just accept the failure, + * and continue. */ + if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0) + log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m"); + } if (mm) (void) munmap(mm, mm_size); |