y2038: elfcore: Use __kernel_old_timeval for process times

We store elapsed time for a crashed process in struct elf_prstatus using 'timeval' structures. Once glibc starts using 64-bit time_t, this becomes incompatible with the kernel's idea of timeval since the structure layout no longer matches on 32-bit architectures. This changes the definition of the elf_prstatus structure to use __kernel_old_timeval instead, which is hardcoded to the currently used binary layout. There is no risk of overflow in y2038 though, because the time values are all relative times, and can store up to 68 years of process elapsed time. There is a risk of applications breaking at build time when they use the new kernel headers and expect the type to be exactly 'timeval' rather than a structure that has the same fields as before. Those applications have to be modified to deal with 64-bit time_t anyway.

Arnd Bergmann committed 8 years ago

Commit e2bb80d1 parent 693737b6 files · +22 −22Browse files

Unified · Split

6 files

arch/mips/kernel/binfmt_elfn32.c +2 −2
arch/mips/kernel/binfmt_elfo32.c +2 −2
fs/binfmt_elf.c +6 −6
fs/binfmt_elf_fdpic.c +6 −6
fs/compat_binfmt_elf.c +2 −2
include/uapi/linux/elfcore.h +4 −4

arch/mips/kernel/binfmt_elfn32.c+2−2

@@ -100,7 +100,7 @@ jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value) · 99 unmodified lines
100	#undef TASK_SIZE	100	#undef TASK_SIZE
101	#define TASK_SIZE TASK_SIZE32	101	#define TASK_SIZE TASK_SIZE32
102		102
103	#undef ns_to_timeval	103	#undef ns_to_kernel_old_timeval
104	#define ns_to_timeval ns_to_old_timeval32	104	#define ns_to_kernel_old_timeval ns_to_old_timeval32
105		105
106	#include "../../../fs/binfmt_elf.c"	106	#include "../../../fs/binfmt_elf.c"

arch/mips/kernel/binfmt_elfo32.c+2−2

@@ -103,7 +103,7 @@ jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value) · 102 unmodified lines
103	#undef TASK_SIZE	103	#undef TASK_SIZE
104	#define TASK_SIZE TASK_SIZE32	104	#define TASK_SIZE TASK_SIZE32
105		105
106	#undef ns_to_timeval	106	#undef ns_to_kernel_old_timeval
107	#define ns_to_timeval ns_to_old_timeval32	107	#define ns_to_kernel_old_timeval ns_to_old_timeval32
108		108
109	#include "../../../fs/binfmt_elf.c"	109	#include "../../../fs/binfmt_elf.c"

fs/binfmt_elf.c+6−6

@@ -1489,18 +1489,18 @@ static void fill_prstatus(struct elf_prstatus *prstatus, · 1488 unmodified lines
1489	* group-wide total, not its individual thread total.	1489	* group-wide total, not its individual thread total.
1490	*/	1490	*/
1491	thread_group_cputime(p, &cputime);	1491	thread_group_cputime(p, &cputime);
1492	prstatus->pr_utime = ns_to_timeval(cputime.utime);	1492	prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
1493	prstatus->pr_stime = ns_to_timeval(cputime.stime);	1493	prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1494	} else {	1494	} else {
1495	u64 utime, stime;	1495	u64 utime, stime;
1496		1496
1497	task_cputime(p, &utime, &stime);	1497	task_cputime(p, &utime, &stime);
1498	prstatus->pr_utime = ns_to_timeval(utime);	1498	prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
1499	prstatus->pr_stime = ns_to_timeval(stime);	1499	prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1500	}	1500	}
1501		1501
1502	prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);	1502	prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
1503	prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);	1503	prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1504	}	1504	}
1505		1505
1506	static int fill_psinfo(struct elf_prpsinfo psinfo, struct task_struct p,	1506	static int fill_psinfo(struct elf_prpsinfo psinfo, struct task_struct p,

fs/binfmt_elf_fdpic.c+6−6

@@ -1359,17 +1359,17 @@ static void fill_prstatus(struct elf_prstatus *prstatus, · 1358 unmodified lines
1359	* group-wide total, not its individual thread total.	1359	* group-wide total, not its individual thread total.
1360	*/	1360	*/
1361	thread_group_cputime(p, &cputime);	1361	thread_group_cputime(p, &cputime);
1362	prstatus->pr_utime = ns_to_timeval(cputime.utime);	1362	prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
1363	prstatus->pr_stime = ns_to_timeval(cputime.stime);	1363	prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1364	} else {	1364	} else {
1365	u64 utime, stime;	1365	u64 utime, stime;
1366		1366
1367	task_cputime(p, &utime, &stime);	1367	task_cputime(p, &utime, &stime);
1368	prstatus->pr_utime = ns_to_timeval(utime);	1368	prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
1369	prstatus->pr_stime = ns_to_timeval(stime);	1369	prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1370	}	1370	}
1371	prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);	1371	prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
1372	prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);	1372	prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1373		1373
1374	prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;	1374	prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1375	prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;	1375	prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;

fs/compat_binfmt_elf.c+2−2

@@ -48,8 +48,8 @@ · 47 unmodified lines
48	#define elf_prstatus compat_elf_prstatus	48	#define elf_prstatus compat_elf_prstatus
49	#define elf_prpsinfo compat_elf_prpsinfo	49	#define elf_prpsinfo compat_elf_prpsinfo
50		50
51	#undef ns_to_timeval	51	#undef ns_to_kernel_old_timeval
52	#define ns_to_timeval ns_to_old_timeval32	52	#define ns_to_kernel_old_timeval ns_to_old_timeval32
53		53
54	/*	54	/*
55	* To use this file, asm/elf.h must define compat_elf_check_arch.	55	* To use this file, asm/elf.h must define compat_elf_check_arch.

include/uapi/linux/elfcore.h+4−4

@@ -53,10 +53,10 @@ struct elf_prstatus · 52 unmodified lines
53	pid_t pr_ppid;	53	pid_t pr_ppid;
54	pid_t pr_pgrp;	54	pid_t pr_pgrp;
55	pid_t pr_sid;	55	pid_t pr_sid;
56	struct timeval pr_utime; /* User time */	56	struct __kernel_old_timeval pr_utime; /* User time */
57	struct timeval pr_stime; /* System time */	57	struct __kernel_old_timeval pr_stime; /* System time */
58	struct timeval pr_cutime; /* Cumulative user time */	58	struct __kernel_old_timeval pr_cutime; /* Cumulative user time */
59	struct timeval pr_cstime; /* Cumulative system time */	59	struct __kernel_old_timeval pr_cstime; /* Cumulative system time */
60	#if 0	60	#if 0
61	long pr_instr; /* Current instruction */	61	long pr_instr; /* Current instruction */
62	#endif	62	#endif