From: He Zhe <[email protected]> memory_corruption_check[{_period|_size}]'s handlers do not check input argument before passing it to kstrtoul or simple_strtoull. The argument would be a NULL pointer if each of the kernel parameters, without its value, is set in command line and thus cause the following panic.
PANIC: early exception 0xe3 IP 10:ffffffff73587c22 error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #2 [ 0.000000] RIP: 0010:kstrtoull+0x2/0x10 ... [ 0.000000] Call Trace [ 0.000000] ? set_corruption_check+0x21/0x49 [ 0.000000] ? do_early_param+0x4d/0x82 [ 0.000000] ? parse_args+0x212/0x330 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_options+0x20/0x23 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_param+0x2d/0x39 [ 0.000000] ? setup_arch+0x2f7/0xbf4 [ 0.000000] ? start_kernel+0x5e/0x4c2 [ 0.000000] ? load_ucode_bsp+0x113/0x12f [ 0.000000] ? secondary_startup_64+0xa5/0xb0 This patch adds checks to prevent the panic and changes some printk to right fashion. Signed-off-by: He Zhe <[email protected]> --- arch/x86/kernel/check.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c index 3339942..d3d65d7 100644 --- a/arch/x86/kernel/check.c +++ b/arch/x86/kernel/check.c @@ -31,6 +31,11 @@ static __init int set_corruption_check(char *arg) ssize_t ret; unsigned long val; + if (!arg) { + pr_err("memory_corruption_check: null option\n"); + return -EINVAL; + } + ret = kstrtoul(arg, 10, &val); if (ret) return ret; @@ -45,6 +50,11 @@ static __init int set_corruption_check_period(char *arg) ssize_t ret; unsigned long val; + if (!arg) { + pr_err("memory_corruption_check_period: null option\n"); + return -EINVAL; + } + ret = kstrtoul(arg, 10, &val); if (ret) return ret; @@ -59,6 +69,11 @@ static __init int set_corruption_check_size(char *arg) char *end; unsigned size; + if (!arg) { + pr_err("memory_corruption_check_size: null option\n"); + return -EINVAL; + } + size = memparse(arg, &end); if (*end == '\0') @@ -113,7 +128,8 @@ void __init setup_bios_corruption_check(void) } if (num_scan_areas) - printk(KERN_INFO "Scanning %d areas for low memory corruption\n", num_scan_areas); + pr_info("Scanning %d areas for low memory corruption\n", + num_scan_areas); } @@ -132,7 +148,7 @@ void check_for_bios_corruption(void) for (; size; addr++, size -= sizeof(unsigned long)) { if (!*addr) continue; - printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n", + pr_err("Corrupted low memory at %p (%lx phys) = %08lx\n", addr, __pa(addr), *addr); corruption = 1; *addr = 0; @@ -157,7 +173,7 @@ static int start_periodic_check_for_corruption(void) if (!num_scan_areas || !memory_corruption_check || corruption_check_period == 0) return 0; - printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n", + pr_info("Scanning for low memory corruption every %d seconds\n", corruption_check_period); /* First time we run the checks right away */ -- 2.7.4
