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).

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).

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: sysv: no llame a sb_bread() con pointers_lock retenido syzbot informa suspensión en contexto atómico en el sistema de archivos SysV [1], porque sb_bread() se llama con rw_spinlock retenido. Un error "write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock" y un error "sb_bread() with write_lock(&pointers_lock)" fueron introducidos por "Reemplazar BKL para bloqueo de cadena con sysvfs-private rwlock" en Linux 2.5.12. Luego, "[PATCH] err1-40: corrección de bloqueo de sysvfs" en Linux 2.6.8 solucionó el error anterior moviendo el bloqueo pointers_lock a las personas que llaman, pero en su lugar introdujo un error "sb_bread() con read_lock(&pointers_lock)" (que hizo que esto problema más fácil de abordar). Al Viro sugirió que por qué no hacer lo que hace get_branch()/get_block()/find_shared() en el sistema de archivos Minix. Y hacer eso es casi una reversión de "[PATCH] err1-40: corrección de bloqueo de sysvfs", excepto que get_branch() de find_shared() se llama sin write_lock(&pointers_lock).