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pstore: replace spinlock_t by raw_spinlock_t

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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>
This commit is contained in:
Wen Yang 2024-08-19 22:59:45 +08:00 committed by Kees Cook
parent a7050ca724
commit 1bf8012fc6
2 changed files with 5 additions and 5 deletions
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8
fs/pstore/platform.c
View File

@ -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();

2
include/linux/pstore.h
View File

@ -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;