Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
pidfs: expose coredump signal
Userspace needs access to the signal that caused the coredump before the
coredumping process has been reaped. Expose it as part of the coredump
information in struct pidfd_info. After the process has been reaped that
info is also available as part of PIDFD_INFO_EXIT's exit_code field.
Link: https://patch.msgid.link/20251028-work-coredump-signal-v1-8-ca449b7b7aa0@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
+24
-13
+19
-11
fs/pidfs.c
+19
-11
fs/pidfs.c
···
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enum pidfs_attr_mask_bits {
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PIDFS_ATTR_BIT_EXIT = 0,
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PIDFS_ATTR_BIT_COREDUMP = 1,
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};
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struct pidfs_attr {
···
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__s32 exit_code;
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};
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__u32 coredump_mask;
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__u32 coredump_signal;
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};
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static struct rb_root pidfs_ino_tree = RB_ROOT;
···
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PIDFD_INFO_CGROUPID | \
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PIDFD_INFO_EXIT | \
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PIDFD_INFO_COREDUMP | \
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PIDFD_INFO_SUPPORTED_MASK)
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PIDFD_INFO_SUPPORTED_MASK | \
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PIDFD_INFO_COREDUMP_SIGNAL)
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static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg)
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{
···
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}
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if (mask & PIDFD_INFO_COREDUMP) {
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kinfo.coredump_mask = READ_ONCE(attr->coredump_mask);
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if (kinfo.coredump_mask)
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kinfo.mask |= PIDFD_INFO_COREDUMP;
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if (test_bit(PIDFS_ATTR_BIT_COREDUMP, &attr->attr_mask)) {
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smp_rmb();
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kinfo.mask |= PIDFD_INFO_COREDUMP | PIDFD_INFO_COREDUMP_SIGNAL;
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kinfo.coredump_mask = attr->coredump_mask;
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kinfo.coredump_signal = attr->coredump_signal;
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}
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}
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task = get_pid_task(pid, PIDTYPE_PID);
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kinfo.coredump_mask = pidfs_coredump_mask(flags);
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kinfo.mask |= PIDFD_INFO_COREDUMP;
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/* No coredump actually took place, so no coredump signal. */
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}
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}
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···
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{
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struct pid *pid = cprm->pid;
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struct pidfs_attr *attr;
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__u32 coredump_mask = 0;
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attr = READ_ONCE(pid->attr);
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VFS_WARN_ON_ONCE(!attr);
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VFS_WARN_ON_ONCE(attr == PIDFS_PID_DEAD);
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/* Note how we were coredumped. */
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coredump_mask = pidfs_coredump_mask(cprm->mm_flags);
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/* Note that we actually did coredump. */
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coredump_mask |= PIDFD_COREDUMPED;
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/* Note how we were coredumped and that we coredumped. */
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attr->coredump_mask = pidfs_coredump_mask(cprm->mm_flags) |
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PIDFD_COREDUMPED;
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/* If coredumping is set to skip we should never end up here. */
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VFS_WARN_ON_ONCE(coredump_mask & PIDFD_COREDUMP_SKIP);
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smp_store_release(&attr->coredump_mask, coredump_mask);
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VFS_WARN_ON_ONCE(attr->coredump_mask & PIDFD_COREDUMP_SKIP);
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/* Expose the signal number that caused the coredump. */
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attr->coredump_signal = cprm->siginfo->si_signo;
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smp_wmb();
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set_bit(PIDFS_ATTR_BIT_COREDUMP, &attr->attr_mask);
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}
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#endif
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+5
-2
include/uapi/linux/pidfd.h
+5
-2
include/uapi/linux/pidfd.h
···
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#define PIDFD_INFO_EXIT (1UL << 3) /* Only returned if requested. */
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#define PIDFD_INFO_COREDUMP (1UL << 4) /* Only returned if requested. */
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#define PIDFD_INFO_SUPPORTED_MASK (1UL << 5) /* Want/got supported mask flags */
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#define PIDFD_INFO_COREDUMP_SIGNAL (1UL << 6) /* Always returned if PIDFD_INFO_COREDUMP is requested. */
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#define PIDFD_INFO_SIZE_VER0 64 /* sizeof first published struct */
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#define PIDFD_INFO_SIZE_VER1 72 /* sizeof second published struct */
···
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__u32 fsuid;
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__u32 fsgid;
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__s32 exit_code;
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-
__u32 coredump_mask;
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__u32 __spare1;
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struct /* coredump info */ {
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__u32 coredump_mask;
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__u32 coredump_signal;
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};
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__u64 supported_mask; /* Mask flags that this kernel supports */
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};
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