CVE-2023-52699

In the Linux kernel, the following vulnerability has been resolved: sysv: don't call sb_bread() with pointers_lock held syzbot is reporting sleep in atomic context in SysV filesystem [1], for sb_bread() is called with rw_spinlock held. A "write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock" bug and a "sb_bread() with write_lock(&pointers_lock)" bug were introduced by "Replace BKL for chain locking with sysvfs-private rwlock" in Linux 2.5.12. Then, "[PATCH] err1-40: sysvfs locking fix" in Linux 2.6.8 fixed the former bug by moving pointers_lock lock to the callers, but instead introduced a "sb_bread() with read_lock(&pointers_lock)" bug (which made this problem easier to hit). Al Viro suggested that why not to do like get_branch()/get_block()/ find_shared() in Minix filesystem does. And doing like that is almost a revert of "[PATCH] err1-40: sysvfs locking fix" except that get_branch() from with find_shared() is called without write_lock(&pointers_lock).

• linux linux kernel (< 4.19.312) • linux linux kernel (>= 4.20 < 5.4.274) • linux linux kernel (>= 5.5 < 5.10.215) • linux linux kernel (>= 5.11 < 5.15.155) • linux linux kernel (>= 5.16 < 6.1.86) • linux linux kernel (>= 6.2 < 6.6.27) • linux linux kernel (>= 6.7 < 6.8.6) • debian debian linux 10.0