diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2026-02-10 11:27:38 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-02-12 15:40:16 -0800 |
| commit | 61dc9f776705d6db6847c101b98fa4f0e9eb6fa3 (patch) | |
| tree | 7fb90c5acde75c910342b16620abdf24a04c9502 | |
| parent | 338ad1e84d15078a9ae46d7dd7466329ae0bfa61 (diff) | |
procfs: fix possible double mmput() in do_procmap_query()
When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY
we return with -ENAMETOOLONG error. After recent changes this condition
happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(),
so original goto out is now wrong and will double-mmput() mm_struct. Fix
by jumping further to clean up only vm_file and name_buf.
Link: https://lkml.kernel.org/r/20260210192738.3041609-1-andrii@kernel.org
Fixes: b5cbacd7f86f ("procfs: avoid fetching build ID while holding VMA lock")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reported-by: Ruikai Peng <ruikai@pwno.io>
Reported-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: syzbot+237b5b985b78c1da9600@syzkaller.appspotmail.com
Cc: Ruikai Peng <ruikai@pwno.io>
Closes: https://lkml.kernel.org/r/CAFD3drOJANTZPuyiqMdqpiRwOKnHwv5QgMNZghCDr-WxdiHvMg@mail.gmail.com
Closes: https://lore.kernel.org/all/698aaf3c.050a0220.3b3015.0088.GAE@google.com/T/#u
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | fs/proc/task_mmu.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 26188a4ad1ab..2f55efc36816 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -780,7 +780,7 @@ static int do_procmap_query(struct mm_struct *mm, void __user *uarg) } else { if (karg.build_id_size < build_id_sz) { err = -ENAMETOOLONG; - goto out; + goto out_file; } karg.build_id_size = build_id_sz; } @@ -808,6 +808,7 @@ static int do_procmap_query(struct mm_struct *mm, void __user *uarg) out: query_vma_teardown(&lock_ctx); mmput(mm); +out_file: if (vm_file) fput(vm_file); kfree(name_buf); |