diff mbox series

ppp: Fix deadlock caused by unsafe-irq lock in ap_get()

Message ID 20240418175910.7641-1-aha310510@gmail.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series ppp: Fix deadlock caused by unsafe-irq lock in ap_get() | expand

Checks

Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 926 this patch: 17
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: jirislaby@kernel.org gregkh@linuxfoundation.org
netdev/build_clang fail Errors and warnings before: 937 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn fail Errors and warnings before: 937 this patch: 17
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 15 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jeongjun Park April 18, 2024, 5:59 p.m. UTC 
read_lock() present in ap_get() is interrupt-vulnerable, so the function needs to be modified.


Reported-by: syzbot+393d0ef63475d9bb1f16@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
---
 drivers/net/ppp/ppp_async.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ppp/ppp_async.c b/drivers/net/ppp/ppp_async.c
index c33c3db3cc08..dc1d4633428a 100644
--- a/drivers/net/ppp/ppp_async.c
+++ b/drivers/net/ppp/ppp_async.c
@@ -133,12 +133,13 @@  static DEFINE_RWLOCK(disc_data_lock);
 static struct asyncppp *ap_get(struct tty_struct *tty)
 {
 	struct asyncppp *ap;
+	unsigned long flags;
 
-	read_lock(&disc_data_lock);
+	flags = read_lock_irqsave(&disc_data_lock);
 	ap = tty->disc_data;
 	if (ap != NULL)
 		refcount_inc(&ap->refcnt);
-	read_unlock(&disc_data_lock);
+	read_unlock_irqrestore(&disc_data_lock, flags);
 	return ap;
 }