linux/fs/proc
Ryan Roberts c70dce4982 fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan
make_uffd_wp_pte() was previously doing:

  pte = ptep_get(ptep);
  ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

But if another thread accessed or dirtied the pte between the first 2
calls, this could lead to loss of that information.  Since
ptep_modify_prot_start() gets and clears atomically, the following is the
correct pattern and prevents any possible race.  Any access after the
first call would see an invalid pte and cause a fault:

  pte = ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

Link: https://lkml.kernel.org/r/20240429114017.182570-1-ryan.roberts@arm.com
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:28:06 -07:00
..
array.c fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats 2024-02-07 21:20:33 -08:00
base.c procfs: move dropping pde and pid from ->evict_inode() to ->free_inode() 2024-02-25 02:10:32 -05:00
bootconfig.c fs/proc: Skip bootloader comment if no embedded kernel parameters 2024-04-09 23:36:18 +09:00
cmdline.c proc: mark /proc/cmdline as permanent 2023-02-02 22:50:02 -08:00
consoles.c proc: consoles: use console_list_lock for list iteration 2022-12-02 11:25:02 +01:00
cpuinfo.c x86/aperfmperf: Replace aperfmperf_get_khz() 2022-04-27 20:22:19 +02:00
devices.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
fd.c file: convert to SLAB_TYPESAFE_BY_RCU 2023-10-19 11:02:48 +02:00
fd.h fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00
generic.c fs: pass the request_mask to generic_fillattr 2023-08-09 08:56:36 +02:00
inode.c vfs-6.9.misc 2024-03-11 09:38:17 -07:00
internal.h proc: Use lsmids instead of lsm names for attrs 2023-11-12 22:54:42 -05:00
interrupts.c
Kconfig crash: split vmcoreinfo exporting code out from crash_core.c 2024-02-23 17:48:22 -08:00
kcore.c crash: split vmcoreinfo exporting code out from crash_core.c 2024-02-23 17:48:22 -08:00
kmsg.c printk changes for 6.1 2022-10-10 11:24:19 -07:00
loadavg.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
Makefile kbuild: make -Woverride-init warnings more consistent 2024-03-31 11:32:26 +09:00
meminfo.c mm: memtest: convert to memtest_report_meminfo() 2023-08-21 13:37:47 -07:00
namespaces.c
nommu.c fs: create helper file_user_path() for user displayed mapped file path 2023-10-19 11:03:15 +02:00
page.c mm: support page_mapcount() on page_has_type() pages 2024-04-24 19:34:26 -07:00
proc_net.c v6.6-fs.proc.uapi 2023-08-28 11:43:19 -07:00
proc_sysctl.c misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
proc_tty.c proc: delete unused <linux/uaccess.h> includes 2022-07-17 17:31:39 -07:00
root.c procfs: make freeing proc_fs_info rcu-delayed 2024-02-25 02:10:32 -05:00
self.c proc: convert to new timestamp accessors 2023-10-18 14:08:26 +02:00
softirqs.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
stat.c proc/stat: remove arch_idle_time() 2023-04-18 16:39:33 -07:00
task_mmu.c fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan 2024-05-05 17:28:06 -07:00
task_nommu.c vfs-6.7.misc 2023-10-30 09:14:19 -10:00
thread_self.c proc: convert to new timestamp accessors 2023-10-18 14:08:26 +02:00
uptime.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
util.c
version.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
vmcore.c proc/vmcore: fix signedness bug in read_from_oldmem() 2023-07-27 13:07:05 -07:00