This adds the pidfd_open() syscall. It allows a caller to retrieve pollable
pidfds for a process which did not get created via CLONE_PIDFD, i.e. for a
process that is created via traditional fork()/clone() calls that is only
referenced by a PID:
int pidfd = pidfd_open(1234, 0);
ret = pidfd_send_signal(pidfd, SIGSTOP, NULL, 0);
With the introduction of pidfds through CLONE_PIDFD it is possible to
created pidfds at process creation time.
However, a lot of processes get created with traditional PID-based calls
such as fork() or clone() (without CLONE_PIDFD). For these processes a
caller can currently not create a pollable pidfd. This is a problem for
Android's low memory killer (LMK) and service managers such as systemd.
Both are examples of tools that want to make use of pidfds to get reliable
notification of process exit for non-parents (pidfd polling) and race-free
signal sending (pidfd_send_signal()). They intend to switch to this API for
process supervision/management as soon as possible. Having no way to get
pollable pidfds from PID-only processes is one of the biggest blockers for
them in adopting this api. With pidfd_open() making it possible to retrieve
pidfds for PID-based processes we enable them to adopt this api.
In line with Arnd's recent changes to consolidate syscall numbers across
architectures, I have added the pidfd_open() syscall to all architectures
at the same time.
Signed-off-by: Christian Brauner <christian(a)brauner.io>
Reviewed-by: Oleg Nesterov <oleg(a)redhat.com>
Acked-by: Arnd Bergmann <arnd(a)arndb.de>
Cc: "Eric W. Biederman" <ebiederm(a)xmission.com>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Joel Fernandes (Google) <joel(a)joelfernandes.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Jann Horn <jannh(a)google.com>
Cc: David Howells <dhowells(a)redhat.com>
Cc: Andy Lutomirsky <luto(a)kernel.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Aleksa Sarai <cyphar(a)cyphar.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Al Viro <viro(a)zeniv.linux.org.uk>
Cc: linux-api(a)vger.kernel.org
---
v1:
- kbuild test robot <lkp(a)intel.com>:
- add missing entry for pidfd_open to arch/arm/tools/syscall.tbl
- Oleg Nesterov <oleg(a)redhat.com>:
- use simpler thread-group leader check
v2:
- Oleg Nesterov <oleg(a)redhat.com>:
- avoid using additional variable
- remove unneeded comment
- Arnd Bergmann <arnd(a)arndb.de>:
- switch from 428 to 434 since the new mount api has taken it
- bump syscall numbers in arch/arm64/include/asm/unistd.h
- Joel Fernandes (Google) <joel(a)joelfernandes.org>:
- switch from ESRCH to EINVAL when the passed-in pid does not refer to a
thread-group leader
- Christian Brauner <christian(a)brauner.io>:
- rebase on v5.2-rc1
- adapt syscall number to account for new mount api syscalls
v3:
- Arnd Bergmann <arnd(a)arndb.de>:
- add missing syscall entries for mips-o32 and mips-n64
---
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +
arch/ia64/kernel/syscalls/syscall.tbl | 1 +
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
include/linux/pid.h | 1 +
include/linux/syscalls.h | 1 +
include/uapi/asm-generic/unistd.h | 4 +-
kernel/fork.c | 2 +-
kernel/pid.c | 43 +++++++++++++++++++++
23 files changed, 68 insertions(+), 3 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 9e7704e44f6d..1db9bbcfb84e 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -473,3 +473,4 @@
541 common fsconfig sys_fsconfig
542 common fsmount sys_fsmount
543 common fspick sys_fspick
+544 common pidfd_open sys_pidfd_open
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index aaf479a9e92d..81e6e1817c45 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -447,3 +447,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 70e6882853c0..e8f7d95a1481 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -44,7 +44,7 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 434
+#define __NR_compat_syscalls 435
#endif
#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index c39e90600bb3..7a3158ccd68e 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -886,6 +886,8 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig)
__SYSCALL(__NR_fsmount, sys_fsmount)
#define __NR_fspick 433
__SYSCALL(__NR_fspick, sys_fspick)
+#define __NR_pidfd_open 434
+__SYSCALL(__NR_pidfd_open, sys_pidfd_open)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index e01df3f2f80d..ecc44926737b 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -354,3 +354,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 7e3d0734b2f3..9a3eb2558568 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -433,3 +433,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 26339e417695..ad706f83c755 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -439,3 +439,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 0e2dd68ade57..97035e19ad03 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -372,3 +372,4 @@
431 n32 fsconfig sys_fsconfig
432 n32 fsmount sys_fsmount
433 n32 fspick sys_fspick
+434 n32 pidfd_open sys_pidfd_open
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 5eebfa0d155c..d7292722d3b0 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -348,3 +348,4 @@
431 n64 fsconfig sys_fsconfig
432 n64 fsmount sys_fsmount
433 n64 fspick sys_fspick
+434 n64 pidfd_open sys_pidfd_open
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 3cc1374e02d0..dba084c92f14 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -421,3 +421,4 @@
431 o32 fsconfig sys_fsconfig
432 o32 fsmount sys_fsmount
433 o32 fspick sys_fspick
+434 o32 pidfd_open sys_pidfd_open
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index c9e377d59232..5022b9e179c2 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -430,3 +430,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 103655d84b4b..f2c3bda2d39f 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -515,3 +515,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index e822b2964a83..6ebacfeaf853 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -436,3 +436,4 @@
431 common fsconfig sys_fsconfig sys_fsconfig
432 common fsmount sys_fsmount sys_fsmount
433 common fspick sys_fspick sys_fspick
+434 common pidfd_open sys_pidfd_open sys_pidfd_open
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 016a727d4357..834c9c7d79fa 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -436,3 +436,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index e047480b1605..c58e71f21129 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -479,3 +479,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ad968b7bac72..43e4429a5272 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -438,3 +438,4 @@
431 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
432 i386 fsmount sys_fsmount __ia32_sys_fsmount
433 i386 fspick sys_fspick __ia32_sys_fspick
+434 i386 pidfd_open sys_pidfd_open __ia32_sys_pidfd_open
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index b4e6f9e6204a..1bee0a77fdd3 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -355,6 +355,7 @@
431 common fsconfig __x64_sys_fsconfig
432 common fsmount __x64_sys_fsmount
433 common fspick __x64_sys_fspick
+434 common pidfd_open __x64_sys_pidfd_open
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 5fa0ee1c8e00..782b81945ccc 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -404,3 +404,4 @@
431 common fsconfig sys_fsconfig
432 common fsmount sys_fsmount
433 common fspick sys_fspick
+434 common pidfd_open sys_pidfd_open
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 3c8ef5a199ca..c938a92eab99 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -67,6 +67,7 @@ struct pid
extern struct pid init_struct_pid;
extern const struct file_operations pidfd_fops;
+extern int pidfd_create(struct pid *pid);
static inline struct pid *get_pid(struct pid *pid)
{
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e2870fe1be5b..989055e0b501 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -929,6 +929,7 @@ asmlinkage long sys_clock_adjtime32(clockid_t which_clock,
struct old_timex32 __user *tx);
asmlinkage long sys_syncfs(int fd);
asmlinkage long sys_setns(int fd, int nstype);
+asmlinkage long sys_pidfd_open(pid_t pid, unsigned int flags);
asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg,
unsigned int vlen, unsigned flags);
asmlinkage long sys_process_vm_readv(pid_t pid,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index a87904daf103..e5684a4512c0 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -844,9 +844,11 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig)
__SYSCALL(__NR_fsmount, sys_fsmount)
#define __NR_fspick 433
__SYSCALL(__NR_fspick, sys_fspick)
+#define __NR_pidfd_open 434
+__SYSCALL(__NR_pidfd_open, sys_pidfd_open)
#undef __NR_syscalls
-#define __NR_syscalls 434
+#define __NR_syscalls 435
/*
* 32 bit systems traditionally used different
diff --git a/kernel/fork.c b/kernel/fork.c
index b4cba953040a..c3df226f47a1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1724,7 +1724,7 @@ const struct file_operations pidfd_fops = {
* Return: On success, a cloexec pidfd is returned.
* On error, a negative errno number will be returned.
*/
-static int pidfd_create(struct pid *pid)
+int pidfd_create(struct pid *pid)
{
int fd;
diff --git a/kernel/pid.c b/kernel/pid.c
index 89548d35eefb..8fc9d94f6ac1 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -37,6 +37,7 @@
#include <linux/syscalls.h>
#include <linux/proc_ns.h>
#include <linux/proc_fs.h>
+#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/idr.h>
@@ -450,6 +451,48 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
return idr_get_next(&ns->idr, &nr);
}
+/**
+ * pidfd_open() - Open new pid file descriptor.
+ *
+ * @pid: pid for which to retrieve a pidfd
+ * @flags: flags to pass
+ *
+ * This creates a new pid file descriptor with the O_CLOEXEC flag set for
+ * the process identified by @pid. Currently, the process identified by
+ * @pid must be a thread-group leader. This restriction currently exists
+ * for all aspects of pidfds including pidfd creation (CLONE_PIDFD cannot
+ * be used with CLONE_THREAD) and pidfd polling (only supports thread group
+ * leaders).
+ *
+ * Return: On success, a cloexec pidfd is returned.
+ * On error, a negative errno number will be returned.
+ */
+SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags)
+{
+ int fd, ret;
+ struct pid *p;
+
+ if (flags)
+ return -EINVAL;
+
+ if (pid <= 0)
+ return -EINVAL;
+
+ p = find_get_pid(pid);
+ if (!p)
+ return -ESRCH;
+
+ ret = 0;
+ rcu_read_lock();
+ if (!pid_task(p, PIDTYPE_TGID))
+ ret = -EINVAL;
+ rcu_read_unlock();
+
+ fd = ret ?: pidfd_create(p);
+ put_pid(p);
+ return fd;
+}
+
void __init pid_idr_init(void)
{
/* Verify no one has done anything silly: */
--
2.21.0
This reverts commit 2b845d4b4acd9422bbb668989db8dc36dfc8f438.
That commit introduces build issues for programs compiled in Thumb mode.
Rather than try to be clever and emit a valid trap instruction on arm32,
which requires special care about big/little endian handling on that
architecture, just emit plain data. Data in the instruction stream is
technically expected on arm32: this is how literal pools are
implemented. Reverting to the prior behavior does exactly that.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
CC: Peter Zijlstra <peterz(a)infradead.org>
CC: Thomas Gleixner <tglx(a)linutronix.de>
CC: Joel Fernandes <joelaf(a)google.com>
CC: Catalin Marinas <catalin.marinas(a)arm.com>
CC: Dave Watson <davejwatson(a)fb.com>
CC: Will Deacon <will.deacon(a)arm.com>
CC: Shuah Khan <shuah(a)kernel.org>
CC: Andi Kleen <andi(a)firstfloor.org>
CC: linux-kselftest(a)vger.kernel.org
CC: "H . Peter Anvin" <hpa(a)zytor.com>
CC: Chris Lameter <cl(a)linux.com>
CC: Russell King <linux(a)arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages(a)gmail.com>
CC: "Paul E . McKenney" <paulmck(a)linux.vnet.ibm.com>
CC: Paul Turner <pjt(a)google.com>
CC: Boqun Feng <boqun.feng(a)gmail.com>
CC: Josh Triplett <josh(a)joshtriplett.org>
CC: Steven Rostedt <rostedt(a)goodmis.org>
CC: Ben Maurer <bmaurer(a)fb.com>
CC: linux-api(a)vger.kernel.org
CC: Andy Lutomirski <luto(a)amacapital.net>
CC: Andrew Morton <akpm(a)linux-foundation.org>
CC: Linus Torvalds <torvalds(a)linux-foundation.org>
CC: Carlos O'Donell <carlos(a)redhat.com>
CC: Florian Weimer <fweimer(a)redhat.com>
---
tools/testing/selftests/rseq/rseq-arm.h | 52 ++-------------------------------
1 file changed, 2 insertions(+), 50 deletions(-)
diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h
index 84f28f147fb6..5f262c54364f 100644
--- a/tools/testing/selftests/rseq/rseq-arm.h
+++ b/tools/testing/selftests/rseq/rseq-arm.h
@@ -5,54 +5,7 @@
* (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
*/
-/*
- * RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand
- * value 0x5de3. This traps if user-space reaches this instruction by mistake,
- * and the uncommon operand ensures the kernel does not move the instruction
- * pointer to attacker-controlled code on rseq abort.
- *
- * The instruction pattern in the A32 instruction set is:
- *
- * e7f5def3 udf #24035 ; 0x5de3
- *
- * This translates to the following instruction pattern in the T16 instruction
- * set:
- *
- * little endian:
- * def3 udf #243 ; 0xf3
- * e7f5 b.n <7f5>
- *
- * pre-ARMv6 big endian code:
- * e7f5 b.n <7f5>
- * def3 udf #243 ; 0xf3
- *
- * ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian
- * code and big-endian data. Ensure the RSEQ_SIG data signature matches code
- * endianness. Prior to ARMv6, -mbig-endian generates big-endian code and data
- * (which match), so there is no need to reverse the endianness of the data
- * representation of the signature. However, the choice between BE32 and BE8
- * is done by the linker, so we cannot know whether code and data endianness
- * will be mixed before the linker is invoked.
- */
-
-#define RSEQ_SIG_CODE 0xe7f5def3
-
-#ifndef __ASSEMBLER__
-
-#define RSEQ_SIG_DATA \
- ({ \
- int sig; \
- asm volatile ("b 2f\n\t" \
- "1: .inst " __rseq_str(RSEQ_SIG_CODE) "\n\t" \
- "2:\n\t" \
- "ldr %[sig], 1b\n\t" \
- : [sig] "=r" (sig)); \
- sig; \
- })
-
-#define RSEQ_SIG RSEQ_SIG_DATA
-
-#endif
+#define RSEQ_SIG 0x53053053
#define rseq_smp_mb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
#define rseq_smp_rmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
@@ -125,8 +78,7 @@ do { \
__rseq_str(table_label) ":\n\t" \
".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
- ".arm\n\t" \
- ".inst " __rseq_str(RSEQ_SIG_CODE) "\n\t" \
+ ".word " __rseq_str(RSEQ_SIG) "\n\t" \
__rseq_str(label) ":\n\t" \
teardown \
"b %l[" __rseq_str(abort_label) "]\n\t"
--
2.11.0
selftests: bpf test_libbpf.sh failed running Linux -next kernel
20190618 and 20190619.
Here is the log from x86_64,
# selftests bpf test_libbpf.sh
bpf: test_libbpf.sh_ #
# [0] libbpf BTF is required, but is missing or corrupted.
libbpf: BTF_is #
# test_libbpf failed at file test_l4lb.o
failed: at_file #
# selftests test_libbpf [FAILED]
test_libbpf: [FAILED]_ #
[FAIL] 29 selftests bpf test_libbpf.sh
selftests: bpf_test_libbpf.sh [FAIL]
Full test log,
https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20190619/testru…
Test results comparison,
https://qa-reports.linaro.org/lkft/linux-next-oe/tests/kselftest/bpf_test_l…
Good linux -next tag: next-20190617
Bad linux -next tag: next-20190618
git branch master
git commit 1c6b40509daf5190b1fd2c758649f7df1da4827b
git repo
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
Best regards
Naresh Kamboju
---------- Forwarded message ---------
From: Jeffrin Thalakkottoor <jeffrin(a)rajagiritech.edu.in>
Date: Fri, Jun 14, 2019 at 12:06 AM
Subject: BUG: KASAN: global-out-of-bounds in ata_exec_internal_sg+0x50f/0xc70
To: <axboe(a)kernel.dk>, <jejb(a)linux.ibm.com>, <martin.petersen(a)oracle.com>
Cc: lkml <linux-kernel(a)vger.kernel.org>, <linux-ide(a)vger.kernel.org>,
<linux-scsi(a)vger.kernel.org>
hello ,
[ 55.169278] ==================================================================
[ 55.169899] BUG: KASAN: global-out-of-bounds in
ata_exec_internal_sg+0x50f/0xc70 [libata]
[ 55.170039] Read of size 16 at addr ffffffffc0723500 by task scsi_eh_1/149
[ 55.186354] The buggy address belongs to the variable:
[ 55.186972] cdb.48295+0x0/0xfffffffffffeab00 [libata]
[ 55.187171] Memory state around the buggy address:
[ 55.187290] ffffffffc0723400: 00 00 fa fa fa fa fa fa 00 00 fa fa
fa fa fa fa
[ 55.187417] ffffffffc0723480: 00 00 00 00 00 00 00 00 05 fa fa fa
fa fa fa fa
[ 55.187544] >ffffffffc0723500: 00 04 fa fa fa fa fa fa 00 00 fa fa
fa fa fa fa
[ 55.187686] ^
[ 55.187810] ffffffffc0723580: 00 00 05 fa fa fa fa fa 00 00 00 00
00 00 00 00
[ 55.187940] ffffffffc0723600: 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00
[ 55.188060] ==================================================================
output of dmesg with the filename kasan.txt attached
--
software engineer
rajagiri school of engineering and technology
=== Overview
arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [1]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.
Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:
1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
pointers")
This patchset extends tagged pointer support to syscall arguments.
As per the proposed ABI change [3], tagged pointers are only allowed to be
passed to syscalls when they point to memory ranges obtained by anonymous
mmap() or sbrk() (see the patchset [3] for more details).
For non-memory syscalls this is done by untaging user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel and stays tagged when the kernel
dereferences the pointer when perfoming user memory accesses.
The mmap and mremap (only new_addr) syscalls do not currently accept
tagged addresses. Architectures may interpret the tag as a background
colour for the corresponding vma.
Other memory syscalls (mprotect, etc.) don't do user memory accesses but
rather deal with memory ranges, and untagged pointers are better suited to
describe memory ranges internally. Thus for memory syscalls we untag
pointers completely when they enter the kernel.
=== Other approaches
One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a custom
wrapper for each ioctl variation, which doesn't seem practical.
An alternative approach to untagging pointers in memory syscalls prologues
is to inspead allow tagged pointers to be passed to find_vma() (and other
vma related functions) and untag them there. Unfortunately, a lot of
find_vma() callers then compare or subtract the returned vma start and end
fields against the pointer that was being searched. Thus this approach
would still require changing all find_vma() callers.
=== Testing
The following testing approaches has been taken to find potential issues
with user pointer untagging:
1. Static testing (with sparse [2] and separately with a custom static
analyzer based on Clang) to track casts of __user pointers to integer
types to find places where untagging needs to be done.
2. Static testing with grep to find parts of the kernel that call
find_vma() (and other similar functions) or directly compare against
vm_start/vm_end fields of vma.
3. Static testing with grep to find parts of the kernel that compare
user pointers with TASK_SIZE or other similar consts and macros.
4. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
a modified syzkaller version that passes tagged pointers to the kernel.
Based on the results of the testing the requried patches have been added
to the patchset.
=== Notes
This patchset is meant to be merged together with "arm64 relaxed ABI" [3].
This patchset is a prerequisite for ARM's memory tagging hardware feature
support [4].
This patchset has been merged into the Pixel 2 & 3 kernel trees and is
now being used to enable testing of Pixel phones with HWASan.
Thanks!
[1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[2] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060…
[3] https://lkml.org/lkml/2019/3/18/819
[4] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architectur…
=== History
Changes in v17:
- The "uaccess: add noop untagged_addr definition" patch is dropped, as it
was merged into upstream named as "uaccess: add noop untagged_addr
definition".
- Merged "mm, arm64: untag user pointers in do_pages_move" into
"mm, arm64: untag user pointers passed to memory syscalls".
- Added "arm64: Introduce prctl() options to control the tagged user
addresses ABI" patch from Catalin.
- Add tags_lib.so to tools/testing/selftests/arm64/.gitignore.
- Added a comment clarifying untagged in mremap.
- Moved untagging back into mlx4_get_umem_mr() for the IB patch.
Changes in v16:
- Moved untagging for memory syscalls from arm64 wrappers back to generic
code.
- Dropped untagging for the following memory syscalls: brk, mmap, munmap;
mremap (only dropped for new_address); mmap_pgoff (not used on arm64);
remap_file_pages (deprecated); shmat, shmdt (work on shared memory).
- Changed kselftest to LD_PRELOAD a shared library that overrides malloc
to return tagged pointers.
- Rebased onto 5.2-rc3.
Changes in v15:
- Removed unnecessary untagging from radeon_ttm_tt_set_userptr().
- Removed unnecessary untagging from amdgpu_ttm_tt_set_userptr().
- Moved untagging to validate_range() in userfaultfd code.
- Moved untagging to ib_uverbs_(re)reg_mr() from mlx4_get_umem_mr().
- Rebased onto 5.1.
Changes in v14:
- Moved untagging for most memory syscalls to an arm64 specific
implementation, instead of doing that in the common code.
- Dropped "net, arm64: untag user pointers in tcp_zerocopy_receive", since
the provided user pointers don't come from an anonymous map and thus are
not covered by this ABI relaxation.
- Dropped "kernel, arm64: untag user pointers in prctl_set_mm*".
- Moved untagging from __check_mem_type() to tee_shm_register().
- Updated untagging for the amdgpu and radeon drivers to cover the MMU
notifier, as suggested by Felix.
- Since this ABI relaxation doesn't actually allow tagged instruction
pointers, dropped the following patches:
- Dropped "tracing, arm64: untag user pointers in seq_print_user_ip".
- Dropped "uprobes, arm64: untag user pointers in find_active_uprobe".
- Dropped "bpf, arm64: untag user pointers in stack_map_get_build_id_offset".
- Rebased onto 5.1-rc7 (37624b58).
Changes in v13:
- Simplified untagging in tcp_zerocopy_receive().
- Looked at find_vma() callers in drivers/, which allowed to identify a
few other places where untagging is needed.
- Added patch "mm, arm64: untag user pointers in get_vaddr_frames".
- Added patch "drm/amdgpu, arm64: untag user pointers in
amdgpu_ttm_tt_get_user_pages".
- Added patch "drm/radeon, arm64: untag user pointers in
radeon_ttm_tt_pin_userptr".
- Added patch "IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr".
- Added patch "media/v4l2-core, arm64: untag user pointers in
videobuf_dma_contig_user_get".
- Added patch "tee/optee, arm64: untag user pointers in check_mem_type".
- Added patch "vfio/type1, arm64: untag user pointers".
Changes in v12:
- Changed untagging in tcp_zerocopy_receive() to also untag zc->address.
- Fixed untagging in prctl_set_mm* to only untag pointers for vma lookups
and validity checks, but leave them as is for actual user space accesses.
- Updated the link to the v2 of the "arm64 relaxed ABI" patchset [3].
- Dropped the documentation patch, as the "arm64 relaxed ABI" patchset [3]
handles that.
Changes in v11:
- Added "uprobes, arm64: untag user pointers in find_active_uprobe" patch.
- Added "bpf, arm64: untag user pointers in stack_map_get_build_id_offset"
patch.
- Fixed "tracing, arm64: untag user pointers in seq_print_user_ip" to
correctly perform subtration with a tagged addr.
- Moved untagged_addr() from SYSCALL_DEFINE3(mprotect) and
SYSCALL_DEFINE4(pkey_mprotect) to do_mprotect_pkey().
- Moved untagged_addr() definition for other arches from
include/linux/memory.h to include/linux/mm.h.
- Changed untagging in strn*_user() to perform userspace accesses through
tagged pointers.
- Updated the documentation to mention that passing tagged pointers to
memory syscalls is allowed.
- Updated the test to use malloc'ed memory instead of stack memory.
Changes in v10:
- Added "mm, arm64: untag user pointers passed to memory syscalls" back.
- New patch "fs, arm64: untag user pointers in fs/userfaultfd.c".
- New patch "net, arm64: untag user pointers in tcp_zerocopy_receive".
- New patch "kernel, arm64: untag user pointers in prctl_set_mm*".
- New patch "tracing, arm64: untag user pointers in seq_print_user_ip".
Changes in v9:
- Rebased onto 4.20-rc6.
- Used u64 instead of __u64 in type casts in the untagged_addr macro for
arm64.
- Added braces around (addr) in the untagged_addr macro for other arches.
Changes in v8:
- Rebased onto 65102238 (4.20-rc1).
- Added a note to the cover letter on why syscall wrappers/shims that untag
user pointers won't work.
- Added a note to the cover letter that this patchset has been merged into
the Pixel 2 kernel tree.
- Documentation fixes, in particular added a list of syscalls that don't
support tagged user pointers.
Changes in v7:
- Rebased onto 17b57b18 (4.19-rc6).
- Dropped the "arm64: untag user address in __do_user_fault" patch, since
the existing patches already handle user faults properly.
- Dropped the "usb, arm64: untag user addresses in devio" patch, since the
passed pointer must come from a vma and therefore be untagged.
- Dropped the "arm64: annotate user pointers casts detected by sparse"
patch (see the discussion to the replies of the v6 of this patchset).
- Added more context to the cover letter.
- Updated Documentation/arm64/tagged-pointers.txt.
Changes in v6:
- Added annotations for user pointer casts found by sparse.
- Rebased onto 050cdc6c (4.19-rc1+).
Changes in v5:
- Added 3 new patches that add untagging to places found with static
analysis.
- Rebased onto 44c929e1 (4.18-rc8).
Changes in v4:
- Added a selftest for checking that passing tagged pointers to the
kernel succeeds.
- Rebased onto 81e97f013 (4.18-rc1+).
Changes in v3:
- Rebased onto e5c51f30 (4.17-rc6+).
- Added linux-arch@ to the list of recipients.
Changes in v2:
- Rebased onto 2d618bdf (4.17-rc3+).
- Removed excessive untagging in gup.c.
- Removed untagging pointers returned from __uaccess_mask_ptr.
Changes in v1:
- Rebased onto 4.17-rc1.
Changes in RFC v2:
- Added "#ifndef untagged_addr..." fallback in linux/uaccess.h instead of
defining it for each arch individually.
- Updated Documentation/arm64/tagged-pointers.txt.
- Dropped "mm, arm64: untag user addresses in memory syscalls".
- Rebased onto 3eb2ce82 (4.16-rc7).
Signed-off-by: Andrey Konovalov <andreyknvl(a)google.com>
Andrey Konovalov (14):
arm64: untag user pointers in access_ok and __uaccess_mask_ptr
lib, arm64: untag user pointers in strn*_user
mm, arm64: untag user pointers passed to memory syscalls
mm, arm64: untag user pointers in mm/gup.c
mm, arm64: untag user pointers in get_vaddr_frames
fs, arm64: untag user pointers in copy_mount_options
userfaultfd, arm64: untag user pointers
drm/amdgpu, arm64: untag user pointers
drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl
IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr
media/v4l2-core, arm64: untag user pointers in
videobuf_dma_contig_user_get
tee/shm, arm64: untag user pointers in tee_shm_register
vfio/type1, arm64: untag user pointers in vaddr_get_pfn
selftests, arm64: add a selftest for passing tagged pointers to kernel
Catalin Marinas (1):
arm64: Introduce prctl() options to control the tagged user addresses
ABI
arch/arm64/include/asm/processor.h | 6 ++
arch/arm64/include/asm/thread_info.h | 1 +
arch/arm64/include/asm/uaccess.h | 11 ++-
arch/arm64/kernel/process.c | 67 +++++++++++++++++++
.../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 2 +
drivers/gpu/drm/radeon/radeon_gem.c | 2 +
drivers/infiniband/hw/mlx4/mr.c | 7 +-
drivers/media/v4l2-core/videobuf-dma-contig.c | 9 +--
drivers/tee/tee_shm.c | 1 +
drivers/vfio/vfio_iommu_type1.c | 2 +
fs/namespace.c | 2 +-
fs/userfaultfd.c | 22 +++---
include/uapi/linux/prctl.h | 5 ++
kernel/sys.c | 16 +++++
lib/strncpy_from_user.c | 3 +-
lib/strnlen_user.c | 3 +-
mm/frame_vector.c | 2 +
mm/gup.c | 4 ++
mm/madvise.c | 2 +
mm/mempolicy.c | 3 +
mm/migrate.c | 2 +-
mm/mincore.c | 2 +
mm/mlock.c | 4 ++
mm/mprotect.c | 2 +
mm/mremap.c | 7 ++
mm/msync.c | 2 +
tools/testing/selftests/arm64/.gitignore | 2 +
tools/testing/selftests/arm64/Makefile | 22 ++++++
.../testing/selftests/arm64/run_tags_test.sh | 12 ++++
tools/testing/selftests/arm64/tags_lib.c | 62 +++++++++++++++++
tools/testing/selftests/arm64/tags_test.c | 18 +++++
32 files changed, 282 insertions(+), 25 deletions(-)
create mode 100644 tools/testing/selftests/arm64/.gitignore
create mode 100644 tools/testing/selftests/arm64/Makefile
create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
create mode 100644 tools/testing/selftests/arm64/tags_lib.c
create mode 100644 tools/testing/selftests/arm64/tags_test.c
--
2.22.0.rc2.383.gf4fbbf30c2-goog