Y2038 June 2016

y2038@lists.linaro.org

40 participants
31 discussions

by Arnd Bergmann

The tstats_show() function prints a ktime_t variable by converting it to struct timespec first. The algorithm is ok, but we want to stop using timespec in general because of the 32-bit time_t overflow problem. This changes the code to use struct timespec64, without any functional change. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- kernel/time/timer_stats.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c index 1adecb4b87c8..087204c733eb 100644 --- a/kernel/time/timer_stats.c +++ b/kernel/time/timer_stats.c @@ -279,7 +279,7 @@ static void print_name_offset(struct seq_file *m, unsigned long addr) static int tstats_show(struct seq_file *m, void *v) { - struct timespec period; + struct timespec64 period; struct entry *entry; unsigned long ms; long events = 0; @@ -295,11 +295,11 @@ static int tstats_show(struct seq_file *m, void *v) time = ktime_sub(time_stop, time_start); - period = ktime_to_timespec(time); + period = ktime_to_timespec64(time); ms = period.tv_nsec / 1000000; seq_puts(m, "Timer Stats Version: v0.3\n"); - seq_printf(m, "Sample period: %ld.%03ld s\n", period.tv_sec, ms); + seq_printf(m, "Sample period: %ld.%03ld s\n", (long)period.tv_sec, ms); if (atomic_read(&overflow_count)) seq_printf(m, "Overflow: %d entries\n", atomic_read(&overflow_count)); seq_printf(m, "Collection: %s\n", timer_stats_active ? "active" : "inactive"); -- 2.9.0

8 years, 6 months

[PATCH] time: avoid timespec in udelay_test

by Arnd Bergmann

udelay_test_single() uses ktime_get_ts() to get two timespec values and calculate the difference between them, while udelay_test_show() uses the same to printk() the current monotonic time. Both of these are y2038 safe on all machines, but we want to get rid of struct timespec anyway, so this converts the code to use ktime_get_ns() and ktime_get_ts64() respectively. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- kernel/time/test_udelay.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/time/test_udelay.c b/kernel/time/test_udelay.c index e622ba365a13..b0928ab3270f 100644 --- a/kernel/time/test_udelay.c +++ b/kernel/time/test_udelay.c @@ -43,13 +43,13 @@ static int udelay_test_single(struct seq_file *s, int usecs, uint32_t iters) int allowed_error_ns = usecs * 5; for (i = 0; i < iters; ++i) { - struct timespec ts1, ts2; + s64 kt1, kt2; int time_passed; - ktime_get_ts(&ts1); + kt1 = ktime_get_ns(); udelay(usecs); - ktime_get_ts(&ts2); - time_passed = timespec_to_ns(&ts2) - timespec_to_ns(&ts1); + kt2 = ktime_get_ns(); + time_passed = kt2 - kt1; if (i == 0 || time_passed < min) min = time_passed; @@ -87,11 +87,11 @@ static int udelay_test_show(struct seq_file *s, void *v) if (usecs > 0 && iters > 0) { return udelay_test_single(s, usecs, iters); } else if (usecs == 0) { - struct timespec ts; + struct timespec64 ts; - ktime_get_ts(&ts); - seq_printf(s, "udelay() test (lpj=%ld kt=%ld.%09ld)\n", - loops_per_jiffy, ts.tv_sec, ts.tv_nsec); + ktime_get_ts64(&ts); + seq_printf(s, "udelay() test (lpj=%ld kt=%lld.%09ld)\n", + loops_per_jiffy, (s64)ts.tv_sec, ts.tv_nsec); seq_puts(s, "usage:\n"); seq_puts(s, "echo USECS [ITERS] > " DEBUGFS_FILENAME "\n"); seq_puts(s, "cat " DEBUGFS_FILENAME "\n"); -- 2.9.0

8 years, 6 months

[PATCH] procfs: avoid 32-bit time_t in /proc/*/stat

by Arnd Bergmann

/proc/stat shows (among lots of other things) the current boottime (i.e. number of seconds since boot). While a 32-bit number is sufficient for this particular case, we want to get rid of the 'struct timespec' suffers from a 32-bit overflow in 2038. This changes the code to use a struct timespec64, which is known to be safe in all cases. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- fs/proc/stat.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/fs/proc/stat.c b/fs/proc/stat.c index 510413eb25b8..7907e456ac4f 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -80,19 +80,17 @@ static u64 get_iowait_time(int cpu) static int show_stat(struct seq_file *p, void *v) { int i, j; - unsigned long jif; u64 user, nice, system, idle, iowait, irq, softirq, steal; u64 guest, guest_nice; u64 sum = 0; u64 sum_softirq = 0; unsigned int per_softirq_sums[NR_SOFTIRQS] = {0}; - struct timespec boottime; + struct timespec64 boottime; user = nice = system = idle = iowait = irq = softirq = steal = 0; guest = guest_nice = 0; - getboottime(&boottime); - jif = boottime.tv_sec; + getboottime64(&boottime); for_each_possible_cpu(i) { user += kcpustat_cpu(i).cpustat[CPUTIME_USER]; @@ -163,12 +161,12 @@ static int show_stat(struct seq_file *p, void *v) seq_printf(p, "\nctxt %llu\n" - "btime %lu\n" + "btime %llu\n" "processes %lu\n" "procs_running %lu\n" "procs_blocked %lu\n", nr_context_switches(), - (unsigned long)jif, + (unsigned long long)boottime.tv_sec, total_forks, nr_running(), nr_iowait()); -- 2.9.0

8 years, 6 months

[PATCH] initramfs: use vfs_stat/lstat directly

by Arnd Bergmann

sys_newlstat is a system call implementation that is meant for user space, and that copies kernel-internal data structure to the user format, which is not needed for in-kernel users. Further, as we rearrange the system call implementation so we can extend it with 64-bit time_t, the prototype for sys_newlstat changes. This changes the initramfs code to use vfs_lstat directly, to get it out of the way of the time_t changes, and make it slightly more efficient in the process. Along the same lines we also replace sys_stat and sys_stat64 with vfs_stat. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- init/do_mounts.h | 22 ++++------------------ init/initramfs.c | 12 ++++++------ 2 files changed, 10 insertions(+), 24 deletions(-) diff --git a/init/do_mounts.h b/init/do_mounts.h index 067af1d9e8b6..282d65bfd674 100644 --- a/init/do_mounts.h +++ b/init/do_mounts.h @@ -19,29 +19,15 @@ static inline int create_dev(char *name, dev_t dev) return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev)); } -#if BITS_PER_LONG == 32 static inline u32 bstat(char *name) { - struct stat64 stat; - if (sys_stat64(name, &stat) != 0) + struct kstat stat; + if (vfs_stat(name, &stat) != 0) return 0; - if (!S_ISBLK(stat.st_mode)) + if (!S_ISBLK(stat.mode)) return 0; - if (stat.st_rdev != (u32)stat.st_rdev) - return 0; - return stat.st_rdev; -} -#else -static inline u32 bstat(char *name) -{ - struct stat stat; - if (sys_newstat(name, &stat) != 0) - return 0; - if (!S_ISBLK(stat.st_mode)) - return 0; - return stat.st_rdev; + return stat.rdev; } -#endif #ifdef CONFIG_BLK_DEV_RAM diff --git a/init/initramfs.c b/init/initramfs.c index b32ad7d97ac9..ce7a04435996 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -311,10 +311,10 @@ static int __init maybe_link(void) static void __init clean_path(char *path, umode_t fmode) { - struct stat st; + struct kstat st; - if (!sys_newlstat(path, &st) && (st.st_mode ^ fmode) & S_IFMT) { - if (S_ISDIR(st.st_mode)) + if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) { + if (S_ISDIR(st.mode)) sys_rmdir(path); else sys_unlink(path); @@ -580,13 +580,13 @@ static void __init clean_rootfs(void) num = sys_getdents64(fd, dirp, BUF_SIZE); while (num > 0) { while (num > 0) { - struct stat st; + struct kstat st; int ret; - ret = sys_newlstat(dirp->d_name, &st); + ret = vfs_lstat(dirp->d_name, &st); WARN_ON_ONCE(ret); if (!ret) { - if (S_ISDIR(st.st_mode)) + if (S_ISDIR(st.mode)) sys_rmdir(dirp->d_name); else sys_unlink(dirp->d_name); -- 2.9.0

8 years, 6 months

[PATCH] staging: comedi: avoid using timeval

by Arnd Bergmann

Comedi uses 32-bit seconds for its timestamps, on both 32-bit and 64-bit machines. For all I can tell, this was originally meant as a 'timespec', which would overflow in 2038 because of the use of a signed 'long' on 32-bit machines, but it is now used as an array of two unsigned 'lsampl_t' values in comedilib, which will only overflow in 2106, on both 32-bit and 64-bit machines. In an effort to get rid of all uses of 'struct timeval' in the kernel, this replaces the internal code with a call to ktime_get_real_ts64() and a comment at the location of the conversion. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- drivers/staging/comedi/comedi_fops.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 629080f39db0..10a8a9245925 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1256,16 +1256,17 @@ static int parse_insn(struct comedi_device *dev, struct comedi_insn *insn, switch (insn->insn) { case INSN_GTOD: { - struct timeval tv; + struct timespec64 tv; if (insn->n != 2) { ret = -EINVAL; break; } - do_gettimeofday(&tv); - data[0] = tv.tv_sec; - data[1] = tv.tv_usec; + ktime_get_real_ts64(&tv); + /* unsigned data safe until 2106 */ + data[0] = (unsigned int)tv.tv_sec; + data[1] = tv.tv_nsec / NSEC_PER_USEC; ret = 2; break; -- 2.9.0

8 years, 6 months

[PATCH] ata: fix "ering" sysfs time printing

by Arnd Bergmann

The sysfs file for the libata error handling has multiple issues in the way it prints time stamps: * it prints a 9-digit nanosecond value using a %06lu format string, which drops some leading zeroes * it converts a 64-bit jiffes value to a timespec using jiffies_to_timespec(), which takes a 'long' argument, so the result is wrong after a jiffies overflow (49 days). * we try to avoid using timespec because that generally overflows in 2038, although this particular usage is ok. This replaces the jiffies_to_timespec call with an open-coded implementation that gets it right. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- drivers/ata/libata-transport.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c index e2d94972962d..7ef16c085058 100644 --- a/drivers/ata/libata-transport.c +++ b/drivers/ata/libata-transport.c @@ -495,12 +495,13 @@ struct ata_show_ering_arg { static int ata_show_ering(struct ata_ering_entry *ent, void *void_arg) { struct ata_show_ering_arg* arg = void_arg; - struct timespec time; + u64 seconds; + u32 rem; - jiffies_to_timespec(ent->timestamp,&time); + seconds = div_u64_rem(ent->timestamp, HZ, &rem); arg->written += sprintf(arg->buf + arg->written, - "[%5lu.%06lu]", - time.tv_sec, time.tv_nsec); + "[%5llu.%09lu]", seconds, + rem * NSEC_PER_SEC / HZ); arg->written += get_ata_err_names(ent->err_mask, arg->buf + arg->written); return 0; -- 2.9.0

8 years, 6 months

[PATCH] staging: comedi: avoid using timeval

by Arnd Bergmann

It depends on user space whether this is safe or not: if programs interpret the data as a signed time_t value, they will be broken in y2038, and we have to redesign the entire interface. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- drivers/staging/comedi/comedi_fops.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 629080f39db0..fe50d1f823c6 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1256,16 +1256,17 @@ static int parse_insn(struct comedi_device *dev, struct comedi_insn *insn, switch (insn->insn) { case INSN_GTOD: { - struct timeval tv; + struct timespec64 tv; if (insn->n != 2) { ret = -EINVAL; break; } - do_gettimeofday(&tv); + ktime_get_real_ts64(&tv); data[0] = tv.tv_sec; - data[1] = tv.tv_usec; + /* unsigned data safe until 2106 */ + data[1] = tv.tv_nsec / NSEC_PER_USEC; ret = 2; break; -- 2.9.0

8 years, 6 months

[PATCH] x86: remove unused efi_get_time function

by Arnd Bergmann

Nothing calls the efi_get_time function on x86, but it does suffer from the 32-bit time_t overflow in 2038. This removes the function, we can always put it back in case we need it later. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- arch/x86/platform/efi/efi.c | 15 --------------- include/linux/efi.h | 1 - 2 files changed, 16 deletions(-) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 56400d03409f..105e34747116 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -97,21 +97,6 @@ static efi_status_t __init phys_efi_set_virtual_address_map( return status; } -void efi_get_time(struct timespec *now) -{ - efi_status_t status; - efi_time_t eft; - efi_time_cap_t cap; - - status = efi.get_time(&eft, &cap); - if (status != EFI_SUCCESS) - pr_err("Oops: efitime: can't read time!\n"); - - now->tv_sec = mktime(eft.year, eft.month, eft.day, eft.hour, - eft.minute, eft.second); - now->tv_nsec = 0; -} - void __init efi_find_mirror(void) { efi_memory_desc_t *md; diff --git a/include/linux/efi.h b/include/linux/efi.h index acb6adace01e..a402a527592f 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -975,7 +975,6 @@ extern u64 efi_mem_desc_end(efi_memory_desc_t *md); extern int efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md); extern void efi_initialize_iomem_resources(struct resource *code_resource, struct resource *data_resource, struct resource *bss_resource); -extern void efi_get_time(struct timespec *now); extern void efi_reserve_boot_services(void); extern int efi_get_fdt_params(struct efi_fdt_params *params); extern struct kobject *efi_kobj; -- 2.9.0

8 years, 6 months

[PATCH v2] aoe: Use 64-bit timestamp in frame

by Tina Ruchandani

'struct frame' uses two variables to store the sent timestamp - 'struct timeval' and jiffies. jiffies is used to avoid discrepancies caused by updates to system time. 'struct timeval' uses 32-bit representation for seconds which will overflow in year 2038. This patch does the following: - Replace the use of 'struct timeval' and jiffies with struct timespec64, which provides a 64-bit seconds timestamp and is year 2038 safe. - timespec64 provides both long range (like jiffies) and high resolution (like timeval). Using monotonic time (ktime_get_ts64) instead of wall-clock time prevents any discrepancies caused by updates to system time. The previous attempt at this patch and related discussion is here: https://lists.linaro.org/pipermail/y2038/2015-May/000245.html As noted previously, the existing code is 2038-safe, as it only uses a delta instead of absolute timestamps. However, this patch is part of a larger attempt to remove _all_ instances of 32-bit timekeeping from the kernel (time_t, struct timeval and struct timespec) since we do not know which of the many instances of their usage are buggy. It is worth noting that there may be a slight performance penalty, due to timespec64 using nanoseconds instead of microseconds. The tsince_hr function contains a 32-bit multiply just like the existing code, but now it also has a 32-bit divide. Suggested-by: Arnd Bergmann <arnd(a)arndb.de> Signed-off-by: Tina Ruchandani <ruchandani.tina(a)gmail.com> -- Changes in v2: - Change use of ktime_t to timespec64 to avoid expensive 64-bit divide in ktime_us_delta --- drivers/block/aoe/aoe.h | 3 +-- drivers/block/aoe/aoecmd.c | 38 +++++++++----------------------------- 2 files changed, 10 insertions(+), 31 deletions(-) diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h index 9220f8e..d587806 100644 --- a/drivers/block/aoe/aoe.h +++ b/drivers/block/aoe/aoe.h @@ -112,8 +112,7 @@ enum frame_flags { struct frame { struct list_head head; u32 tag; - struct timeval sent; /* high-res time packet was sent */ - u32 sent_jiffs; /* low-res jiffies-based sent time */ + struct timespec64 sent; ulong waited; ulong waited_total; struct aoetgt *t; /* parent target I belong to */ diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c index d597e43..4df542f 100644 --- a/drivers/block/aoe/aoecmd.c +++ b/drivers/block/aoe/aoecmd.c @@ -398,8 +398,7 @@ aoecmd_ata_rw(struct aoedev *d) skb = skb_clone(f->skb, GFP_ATOMIC); if (skb) { - do_gettimeofday(&f->sent); - f->sent_jiffs = (u32) jiffies; + ktime_get_ts64(&f->sent); __skb_queue_head_init(&queue); __skb_queue_tail(&queue, skb); aoenet_xmit(&queue); @@ -489,8 +488,7 @@ resend(struct aoedev *d, struct frame *f) skb = skb_clone(skb, GFP_ATOMIC); if (skb == NULL) return; - do_gettimeofday(&f->sent); - f->sent_jiffs = (u32) jiffies; + ktime_get_ts64(&f->sent); __skb_queue_head_init(&queue); __skb_queue_tail(&queue, skb); aoenet_xmit(&queue); @@ -499,32 +497,17 @@ resend(struct aoedev *d, struct frame *f) static int tsince_hr(struct frame *f) { - struct timeval now; + struct timespec64 now, delta; int n; - do_gettimeofday(&now); - n = now.tv_usec - f->sent.tv_usec; - n += (now.tv_sec - f->sent.tv_sec) * USEC_PER_SEC; + ktime_get_ts64(&now); + delta = timespec64_sub(now, f->sent); + n = ((int32_t) (delta.tv_sec)) * USEC_PER_SEC + + delta.tv_nsec / NSEC_PER_USEC; if (n < 0) n = -n; - /* For relatively long periods, use jiffies to avoid - * discrepancies caused by updates to the system time. - * - * On system with HZ of 1000, 32-bits is over 49 days - * worth of jiffies, or over 71 minutes worth of usecs. - * - * Jiffies overflow is handled by subtraction of unsigned ints: - * (gdb) print (unsigned) 2 - (unsigned) 0xfffffffe - * $3 = 4 - * (gdb) - */ - if (n > USEC_PER_SEC / 4) { - n = ((u32) jiffies) - f->sent_jiffs; - n *= USEC_PER_SEC / HZ; - } - return n; } @@ -589,7 +572,6 @@ reassign_frame(struct frame *f) nf->waited = 0; nf->waited_total = f->waited_total; nf->sent = f->sent; - nf->sent_jiffs = f->sent_jiffs; f->skb = skb; return nf; @@ -633,8 +615,7 @@ probe(struct aoetgt *t) skb = skb_clone(f->skb, GFP_ATOMIC); if (skb) { - do_gettimeofday(&f->sent); - f->sent_jiffs = (u32) jiffies; + ktime_get_ts64(&f->sent); __skb_queue_head_init(&queue); __skb_queue_tail(&queue, skb); aoenet_xmit(&queue); @@ -1474,8 +1455,7 @@ aoecmd_ata_id(struct aoedev *d) skb = skb_clone(skb, GFP_ATOMIC); if (skb) { - do_gettimeofday(&f->sent); - f->sent_jiffs = (u32) jiffies; + ktime_get_ts64(&f->sent); } return skb; -- 2.8.0.rc3.226.g39d4020

8 years, 6 months

Re: [Y2038] [PATCH 04/21] fs: Replace CURRENT_TIME with current_fs_time() for inode timestamps

by Ryusuke Konishi

for nilfs2 bits: Acked-by: Ryusuke Konishi <konishi.ryusuke(a)lab.ntt.co.jp> Thanks, Ryusuke Konishi

8 years, 6 months

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Y2038 June 2016