pstore: replace spinlock_t by raw_spinlock_t

pstore_dump() is called when both preemption and local IRQ are disabled,
and a spinlock is obtained, which is problematic for the RT kernel because
in this configuration, spinlocks are sleep locks.

Replace the spinlock_t with raw_spinlock_t to avoid sleeping in atomic context.

Signed-off-by: Wen Yang <wen.yang@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: linux-hardening@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20240819145945.61274-1-wen.yang@linux.dev
Signed-off-by: Kees Cook <kees@kernel.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 3497ede88aa0162863fff69c8fa060ec99415be2..84719e2bcbc456021a17f550c67e4b942ac5b03f 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -288,13 +288,13 @@ static void pstore_dump(struct kmsg_dumper *dumper,
        why = kmsg_dump_reason_str(reason);
 
        if (pstore_cannot_block_path(reason)) {
-               if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
+               if (!raw_spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
                        pr_err("dump skipped in %s path because of concurrent dump\n",
                                        in_nmi() ? "NMI" : why);
                        return;
                }
        } else {
-               spin_lock_irqsave(&psinfo->buf_lock, flags);
+               raw_spin_lock_irqsave(&psinfo->buf_lock, flags);
        }
 
        kmsg_dump_rewind(&iter);
@@ -364,7 +364,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
                total += record.size;
                part++;
        }
-       spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+       raw_spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 
        if (saved_ret) {
                pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
@@ -503,7 +503,7 @@ int pstore_register(struct pstore_info *psi)
                psi->write_user = pstore_write_user_compat;
        psinfo = psi;
        mutex_init(&psinfo->read_mutex);
-       spin_lock_init(&psinfo->buf_lock);
+       raw_spin_lock_init(&psinfo->buf_lock);
 
        if (psi->flags & PSTORE_FLAGS_DMESG)
                allocate_buf_for_compression();

diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 638507a3c8ff194e22a27955ca40dab238328f2f..fed601053c5197e7606dd9e1e45f7983febc45fa 100644 (file)
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -182,7 +182,7 @@ struct pstore_info {
        struct module   *owner;
        const char      *name;
 
-       spinlock_t      buf_lock;
+       raw_spinlock_t  buf_lock;
        char            *buf;
        size_t          bufsize;