This is a note to let you know that I've just added the patch titled
closures: Change BUG_ON() to WARN_ON()
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
closures-change-bug_on-to-warn_on.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 729ccbb2fa7d7b2dd43618a5346b3670ba77e9bd
Author: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Date: Thu Jun 20 09:45:09 2024 -0400
closures: Change BUG_ON() to WARN_ON()
[ Upstream commit 339b84ab6b1d66900c27bd999271cb2ae40ce812 ]
If a BUG_ON() can be hit in the wild, it shouldn't be a BUG_ON()
For reference, this has popped up once in the CI, and we'll need more
info to debug it:
03240 ------------[ cut here ]------------
03240 kernel BUG at lib/closure.c:21!
03240 kernel BUG at lib/closure.c:21!
03240 Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
03240 Modules linked in:
03240 CPU: 15 PID: 40534 Comm: kworker/u80:1 Not tainted 6.10.0-rc4-ktest-ga56da69799bd #25570
03240 Hardware name: linux,dummy-virt (DT)
03240 Workqueue: btree_update btree_interior_update_work
03240 pstate: 00001005 (nzcv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--)
03240 pc : closure_put+0x224/0x2a0
03240 lr : closure_put+0x24/0x2a0
03240 sp : ffff0000d12071c0
03240 x29: ffff0000d12071c0 x28: dfff800000000000 x27: ffff0000d1207360
03240 x26: 0000000000000040 x25: 0000000000000040 x24: 0000000000000040
03240 x23: ffff0000c1f20180 x22: 0000000000000000 x21: ffff0000c1f20168
03240 x20: 0000000040000000 x19: ffff0000c1f20140 x18: 0000000000000001
03240 x17: 0000000000003aa0 x16: 0000000000003ad0 x15: 1fffe0001c326974
03240 x14: 0000000000000a1e x13: 0000000000000000 x12: 1fffe000183e402d
03240 x11: ffff6000183e402d x10: dfff800000000000 x9 : ffff6000183e402e
03240 x8 : 0000000000000001 x7 : 00009fffe7c1bfd3 x6 : ffff0000c1f2016b
03240 x5 : ffff0000c1f20168 x4 : ffff6000183e402e x3 : ffff800081391954
03240 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 00000000a8000000
03240 Call trace:
03240 closure_put+0x224/0x2a0
03240 bch2_check_for_deadlock+0x910/0x1028
03240 bch2_six_check_for_deadlock+0x1c/0x30
03240 six_lock_slowpath.isra.0+0x29c/0xed0
03240 six_lock_ip_waiter+0xa8/0xf8
03240 __bch2_btree_node_lock_write+0x14c/0x298
03240 bch2_trans_lock_write+0x6d4/0xb10
03240 __bch2_trans_commit+0x135c/0x5520
03240 btree_interior_update_work+0x1248/0x1c10
03240 process_scheduled_works+0x53c/0xd90
03240 worker_thread+0x370/0x8c8
03240 kthread+0x258/0x2e8
03240 ret_from_fork+0x10/0x20
03240 Code: aa1303e0 d63f0020 a94363f7 17ffff8c (d4210000)
03240 ---[ end trace 0000000000000000 ]---
03240 Kernel panic - not syncing: Oops - BUG: Fatal exception
03240 SMP: stopping secondary CPUs
03241 SMP: failed to stop secondary CPUs 13,15
03241 Kernel Offset: disabled
03241 CPU features: 0x00,00000003,80000008,4240500b
03241 Memory Limit: none
03241 ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]---
03246 ========= FAILED TIMEOUT copygc_torture_no_checksum in 7200s
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/lib/closure.c b/lib/closure.c
index c16540552d61b..99380d9b4aa94 100644
--- a/lib/closure.c
+++ b/lib/closure.c
@@ -17,12 +17,18 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
{
int r = flags & CLOSURE_REMAINING_MASK;
- BUG_ON(flags & CLOSURE_GUARD_MASK);
- BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
+ if (WARN(flags & CLOSURE_GUARD_MASK,
+ "closure has guard bits set: %x (%u)",
+ flags & CLOSURE_GUARD_MASK, (unsigned) __fls(r)))
+ r &= ~CLOSURE_GUARD_MASK;
if (!r) {
smp_acquire__after_ctrl_dep();
+ WARN(flags & ~CLOSURE_DESTRUCTOR,
+ "closure ref hit 0 with incorrect flags set: %x (%u)",
+ flags & ~CLOSURE_DESTRUCTOR, (unsigned) __fls(flags));
+
cl->closure_get_happened = false;
if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
