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-rw-r--r--src/server.c101
1 files changed, 68 insertions, 33 deletions
diff --git a/src/server.c b/src/server.c
index 5c1400510..1d6de48a0 100644
--- a/src/server.c
+++ b/src/server.c
@@ -3762,7 +3762,7 @@ static int smapsGetSharedDirty(unsigned long addr) {
FILE *f;
f = fopen("/proc/self/smaps", "r");
- serverAssert(f);
+ if (!f) return -1;
while (1) {
if (!fgets(buf, sizeof(buf), f))
@@ -3773,8 +3773,8 @@ static int smapsGetSharedDirty(unsigned long addr) {
in_mapping = from <= addr && addr < to;
if (in_mapping && !memcmp(buf, "Shared_Dirty:", 13)) {
- ret = sscanf(buf, "%*s %d", &val);
- serverAssert(ret == 1);
+ sscanf(buf, "%*s %d", &val);
+ /* If parsing fails, we remain with val == -1 */
break;
}
}
@@ -3788,23 +3788,33 @@ static int smapsGetSharedDirty(unsigned long addr) {
* kernel is affected.
* The bug was fixed in commit ff1712f953e27f0b0718762ec17d0adb15c9fd0b
* titled: "arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect()"
- * Return 1 if the kernel seems to be affected, and 0 otherwise. */
+ * Return -1 on unexpected test failure, 1 if the kernel seems to be affected,
+ * and 0 otherwise. */
int linuxMadvFreeForkBugCheck(void) {
- int ret, pipefd[2];
+ int ret, pipefd[2] = { -1, -1 };
pid_t pid;
- char *p, *q, bug_found = 0;
- const long map_size = 3 * 4096;
+ char *p = NULL, *q;
+ int bug_found = 0;
+ long page_size = sysconf(_SC_PAGESIZE);
+ long map_size = 3 * page_size;
/* Create a memory map that's in our full control (not one used by the allocator). */
p = mmap(NULL, map_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
- serverAssert(p != MAP_FAILED);
+ if (p == MAP_FAILED) {
+ serverLog(LL_WARNING, "Failed to mmap(): %s", strerror(errno));
+ return -1;
+ }
- q = p + 4096;
+ q = p + page_size;
/* Split the memory map in 3 pages by setting their protection as RO|RW|RO to prevent
* Linux from merging this memory map with adjacent VMAs. */
- ret = mprotect(q, 4096, PROT_READ | PROT_WRITE);
- serverAssert(!ret);
+ ret = mprotect(q, page_size, PROT_READ | PROT_WRITE);
+ if (ret < 0) {
+ serverLog(LL_WARNING, "Failed to mprotect(): %s", strerror(errno));
+ bug_found = -1;
+ goto exit;
+ }
/* Write to the page once to make it resident */
*(volatile char*)q = 0;
@@ -3813,8 +3823,16 @@ int linuxMadvFreeForkBugCheck(void) {
#ifndef MADV_FREE
#define MADV_FREE 8
#endif
- ret = madvise(q, 4096, MADV_FREE);
- serverAssert(!ret);
+ ret = madvise(q, page_size, MADV_FREE);
+ if (ret < 0) {
+ /* MADV_FREE is not available on older kernels that are presumably
+ * not affected. */
+ if (errno == EINVAL) goto exit;
+
+ serverLog(LL_WARNING, "Failed to madvise(): %s", strerror(errno));
+ bug_found = -1;
+ goto exit;
+ }
/* Write to the page after being marked for freeing, this is supposed to take
* ownership of that page again. */
@@ -3822,37 +3840,47 @@ int linuxMadvFreeForkBugCheck(void) {
/* Create a pipe for the child to return the info to the parent. */
ret = pipe(pipefd);
- serverAssert(!ret);
+ if (ret < 0) {
+ serverLog(LL_WARNING, "Failed to create pipe: %s", strerror(errno));
+ bug_found = -1;
+ goto exit;
+ }
/* Fork the process. */
pid = fork();
- serverAssert(pid >= 0);
- if (!pid) {
- /* Child: check if the page is marked as dirty, expecing 4 (kB).
+ if (pid < 0) {
+ serverLog(LL_WARNING, "Failed to fork: %s", strerror(errno));
+ bug_found = -1;
+ goto exit;
+ } else if (!pid) {
+ /* Child: check if the page is marked as dirty, page_size in kb.
* A value of 0 means the kernel is affected by the bug. */
- if (!smapsGetSharedDirty((unsigned long)q))
+ ret = smapsGetSharedDirty((unsigned long) q);
+ if (!ret)
bug_found = 1;
+ else if (ret == -1) /* Failed to read */
+ bug_found = -1;
- ret = write(pipefd[1], &bug_found, 1);
- serverAssert(ret == 1);
-
+ if (write(pipefd[1], &bug_found, sizeof(bug_found)) < 0)
+ serverLog(LL_WARNING, "Failed to write to parent: %s", strerror(errno));
exit(0);
} else {
/* Read the result from the child. */
- ret = read(pipefd[0], &bug_found, 1);
- serverAssert(ret == 1);
+ ret = read(pipefd[0], &bug_found, sizeof(bug_found));
+ if (ret < 0) {
+ serverLog(LL_WARNING, "Failed to read from child: %s", strerror(errno));
+ bug_found = -1;
+ }
/* Reap the child pid. */
- serverAssert(waitpid(pid, NULL, 0) == pid);
+ waitpid(pid, NULL, 0);
}
+exit:
/* Cleanup */
- ret = close(pipefd[0]);
- serverAssert(!ret);
- ret = close(pipefd[1]);
- serverAssert(!ret);
- ret = munmap(p, map_size);
- serverAssert(!ret);
+ if (pipefd[0] != -1) close(pipefd[0]);
+ if (pipefd[1] != -1) close(pipefd[1]);
+ if (p != NULL) munmap(p, map_size);
return bug_found;
}
@@ -4343,10 +4371,17 @@ int main(int argc, char **argv) {
#ifdef __linux__
linuxMemoryWarnings();
#if defined (__arm64__)
- if (linuxMadvFreeForkBugCheck()) {
- serverLog(LL_WARNING,"WARNING Your kernel has a bug that could lead to data corruption during background save. Please upgrade to the latest stable kernel.");
+ int ret;
+ if ((ret = linuxMadvFreeForkBugCheck())) {
+ if (ret == 1)
+ serverLog(LL_WARNING,"WARNING Your kernel has a bug that could lead to data corruption during background save. "
+ "Please upgrade to the latest stable kernel.");
+ else
+ serverLog(LL_WARNING, "Failed to test the kernel for a bug that could lead to data corruption during background save. "
+ "Your system could be affected, please report this error.");
if (!checkIgnoreWarning("ARM64-COW-BUG")) {
- serverLog(LL_WARNING,"Redis will now exit to prevent data corruption. Note that it is possible to suppress this warning by setting the following config: ignore-warnings ARM64-COW-BUG");
+ serverLog(LL_WARNING,"Redis will now exit to prevent data corruption. "
+ "Note that it is possible to suppress this warning by setting the following config: ignore-warnings ARM64-COW-BUG");
exit(1);
}
}