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| author | Xie Yuanbin <xieyuanbin1@huawei.com> | 2026-07-28 03:16:42 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2026-08-05 16:15:51 +0100 |
| commit | 1039bffd6ae9c75b42b7d148d6c1106134107b66 (patch) | |
| tree | e8ee4ac80f87e2ad1b6b0c877eccbb62b0915c02 /tools/perf/trace/strace | |
| download | linux-stable-1039bffd6ae9c75b42b7d148d6c1106134107b66.tar.gz linux-stable-1039bffd6ae9c75b42b7d148d6c1106134107b66.zip | |
ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted
When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().
If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.
Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.
For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.
Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.
Co-developed-by: Qi Xi <xiqi2@huawei.com>
Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'tools/perf/trace/strace')
| -rw-r--r-- | tools/perf/trace/strace/groups/file | 20 | ||||
| -rw-r--r-- | tools/perf/trace/strace/groups/string | 65 |
2 files changed, 85 insertions, 0 deletions
diff --git a/tools/perf/trace/strace/groups/file b/tools/perf/trace/strace/groups/file new file mode 100644 index 000000000..722e25d20 --- /dev/null +++ b/tools/perf/trace/strace/groups/file @@ -0,0 +1,20 @@ +access +chmod +creat +execve +faccessat +getcwd +lstat +mkdir +open +openat +quotactl +read +readlink +rename +rmdir +stat +statfs +symlink +unlink +write diff --git a/tools/perf/trace/strace/groups/string b/tools/perf/trace/strace/groups/string new file mode 100644 index 000000000..c87129a3e --- /dev/null +++ b/tools/perf/trace/strace/groups/string @@ -0,0 +1,65 @@ +access +acct +add_key +chdir +chmod +chown +chroot +creat +delete_module +execve +execveat +faccessat +fchmodat +fchownat +fgetxattr +finit_module +fremovexattr +fsetxattr +futimesat +getxattr +inotify_add_watch +lchown +lgetxattr +link +linkat +listxattr +llistxattr +lremovexattr +lsetxattr +lstat +memfd_create +mkdir +mkdirat +mknod +mknodat +mq_open +mq_timedsend +mq_unlink +name_to_handle_at +newfstatat +open +openat +pivot_root +pwrite64 +quotactl +readlink +readlinkat +removexattr +rename +renameat +renameat2 +request_key +rmdir +setxattr +stat +statfs +statx +swapoff +swapon +symlink +symlinkat +truncate +unlink +unlinkat +utimensat |