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Wythe" , Dust Li , Mahanta Jambigi , David Miller , Jakub Kicinski , Paolo Abeni , Eric Dumazet , Andrew Lunn Cc: Tony Lu , Wen Gu , netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Simon Horman References: <20260904094446.1342654-1-wintera@linux.ibm.com> Content-Language: en-US From: Sidraya Jayagond In-Reply-To: <20260904094446.1342654-1-wintera@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: XIJpfnH_Djy2oYj0-2dy0pWJbcfSQF4R X-Authority-Analysis: v=2.4 cv=RIaD2Yi+ c=1 sm=1 tr=0 ts=6a9e5911 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=PJIUKE5LPszcPwIOA98A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA3MDA2MyBTYWx0ZWRfX7BCweXQ3uFER dwt2nYYEEZ7fQIDlv5efqUr6mwAvcncnHNILlOAlUflELzvcdh7qJq/tNmEBbXujVMdQxcmtl8q CXi7cN9f1xyLp9Tcotd5Ml8xgsS7qvA= X-Proofpoint-ORIG-GUID: xDTB_7dKXmky6dfhkdF6pdwzLWNCzrWG X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA3MDA2MyBTYWx0ZWRfX/rpnn0W0dOiH dynelGnCq0Yh8BzPdCV4XAg0NnKS5GMy9kZkabAUcz/joKzoKZ89xlzgfBuDfMvzu78uK9y0vlm rUGpR7aUt5efrnYttgcbXi6znVTjdist348QYvh7zs6Xg2A+PvWefK1QF2ayNvfBPBJsrXIIVxb LbOBOkno+v9DeIvwnbOdZjVYk/cLnWOH1ocyv/T9Yy1jqLKeyfsKEgO+gKN/j734qJKA4w5ZYvP 3cOxJg4edl7tAOSY+o6ytAkuKPzLPAESXucmy7Iy3ylcfP0D2CNP52e7bRtAS7QFIXTGtCLqsqw q5+pLV2FFtJZ7/ZJuAUhqjSIbsu7Z2y/7BIZunXG/53AJQFlb8DYcJLEX6Y8tcElNVt4iJ4bxPZ GMTyNwA1mSHbi6z6rkI3rAX5cfwGrp0n8D1cnyFq8Ck5Uk7IsQuLkv17RWf76elGBYWy8TkaIQ2 LKSAtu6bjz5GdfQVblA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-07_01,2026-09-03_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 priorityscore=1501 bulkscore=0 adultscore=0 phishscore=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609070063 On 04/09/26 3:14 pm, Alexandra Winter wrote: > dibs->lock is acquired in process context and interrupt context > (ism_handle_irq()). So always use spin_lock_irqsave() in process context. > > Note that this is not a real deadlock, as dibs_lo devices don't have > any interrupt context. > > Example warning: > [ 153.760872] ================================ > [ 153.760878] WARNING: inconsistent lock state > [ 153.760885] 7.2.0-15871-g544d85de4dc2 #16 Not tainted > [ 153.760891] -------------------------------- > [ 153.760896] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. > [ 153.760901] python3/5134 [HC0[0]:SC0[2]:HE1:SE0] takes: > [ 153.760909] 0001222c0fe72428 (&dibs->lock){?...}-{2:2}, at: dibs_lo_move_data+0x1ce/0x380 > [ 153.760932] {IN-HARDIRQ-W} state was registered at: > [ 153.760937] __lock_acquire+0x59c/0x15d0 > [ 153.760947] lock_acquire.part.0+0x11c/0x290 > [ 153.760953] lock_acquire+0xb4/0x1e0 > [ 153.760959] _raw_spin_lock+0x58/0xb0 > [ 153.760966] ism_handle_irq+0x80/0x3f0 [ism] > [ 153.760974] __handle_irq_event_percpu+0x282/0x920 > [ 153.760983] handle_irq_event_percpu+0x26/0xe0 > [ 153.760989] handle_percpu_irq+0x10e/0x1a0 > [ 153.760997] handle_irq_desc+0xa6/0x100 > [ 153.761003] zpci_floating_irq_handler+0x3ca/0x610 > [ 153.761011] do_airq_interrupt+0x206/0x500 > [ 153.761018] __handle_irq_event_percpu+0x282/0x920 > [ 153.761025] handle_irq_event_percpu+0x26/0xe0 > [ 153.761031] handle_percpu_irq+0x10e/0x1a0 > [ 153.761039] handle_irq_desc+0xa6/0x100 > [ 153.761045] do_irq_async+0xec/0x150 > [ 153.761052] do_io_irq+0x150/0x2e0 > [ 153.761060] io_int_handler+0xec/0x118 > [ 153.761066] arch_cpu_idle+0x120/0x130 > [ 153.761118] arch_cpu_idle+0xbe/0x130 > [ 153.761124] s390_enter_idle+0x20/0x30 > [ 153.761131] cpuidle_enter_state+0xb6/0x440 > [ 153.761138] cpuidle_enter+0x64/0xb0 > [ 153.761144] cpuidle_idle_call+0x174/0x380 > [ 153.761151] do_idle+0x16e/0x250 > [ 153.761157] cpu_startup_entry+0x70/0x80 > [ 153.761163] smp_start_secondary+0x36e/0x440 > [ 153.761171] restart_int_handler+0x72/0x88 > [ 153.761178] irq event stamp: 46536 > [ 153.761182] hardirqs last enabled at (46536): [<000127b697450a90>] __local_bh_enable_ip+0x140/0x270 > [ 153.761193] hardirqs last disabled at (46535): [<000127b697450b20>] __local_bh_enable_ip+0x1d0/0x270 > [ 153.761202] softirqs last enabled at (46532): [<000127b6185f82c8>] smc_close_active+0x438/0xba0 [smc] > [ 153.761232] softirqs last disabled at (46534): [<000127b6185ee998>] smc_cdc_get_slot_and_msg_send+0x218/0x370 [smc] > [ 153.761257] > other info that might help us debug this: > [ 153.761262] Possible unsafe locking scenario: > > [ 153.761267] CPU0 > [ 153.761271] ---- > [ 153.761274] lock(&dibs->lock); > [ 153.761282] > [ 153.761286] lock(&dibs->lock); > [ 153.761294] > *** DEADLOCK *** > > [ 153.761299] locks held by python3/5134: 3, last CPU#1: > [ 153.761305] #0: 0001222bab975f50 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release+0x7e/0x230 > [ 153.761329] #1: 0001222ba5450378 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_close_active+0x438/0xba0 [smc] > [ 153.761360] #2: 0001222ba54508a0 (&smc->conn.send_lock){+...}-{2:2}, at: smc_cdc_get_slot_and_msg_send+0x218/0x370 [smc] > [ 153.761394] > stack backtrace: > [ 153.761400] CPU: 1 UID: 0 PID: 5134 Comm: python3 Not tainted 7.2.0-15871-g544d85de4dc2 #16 PREEMPT > [ 153.761406] Hardware name: IBM 3931 A01 703 (LPAR) > [ 153.761408] Call Trace: > [ 153.761409] [<000127b697366190>] dump_stack_lvl+0xe8/0x140 > [ 153.761415] [<000127b6975ccc8c>] print_usage_bug.part.0+0x2ec/0x3a0 > [ 153.761419] [<000127b6975cd454>] mark_lock_irq+0x714/0xa20 > [ 153.761422] [<000127b6975cda52>] mark_lock+0x2f2/0x790 > [ 153.761426] [<000127b6975ce2e6>] mark_usage+0x136/0x1c0 > [ 153.761430] [<000127b6975ce90c>] __lock_acquire+0x59c/0x15d0 > [ 153.761433] [<000127b6975cfa5c>] lock_acquire.part.0+0x11c/0x290 > [ 153.761437] [<000127b6975cfc84>] lock_acquire+0xb4/0x1e0 > [ 153.761441] [<000127b699d02a98>] _raw_spin_lock+0x58/0xb0 > [ 153.761444] [<000127b6992ca4fe>] dibs_lo_move_data+0x1ce/0x380 > [ 153.761449] [<000127b6185f0912>] smcd_tx_ism_write+0x182/0x250 [smc] > [ 153.761469] [<000127b6185ee4c6>] smcd_cdc_msg_send+0x156/0x410 [smc] > [ 153.761487] [<000127b6185ee9a2>] smc_cdc_get_slot_and_msg_send+0x222/0x370 [smc] > [ 153.761507] [<000127b6185f8370>] smc_close_active+0x4e0/0xba0 [smc] > [ 153.761526] [<000127b6185a293c>] __smc_release+0x4ac/0x6a0 [smc] > [ 153.761546] [<000127b6185a2c6e>] smc_release+0x13e/0x480 [smc] > [ 153.761565] [<000127b6994544d4>] __sock_release+0xa4/0x230 > [ 153.761569] [<000127b69945468c>] sock_close+0x2c/0x40 > [ 153.761573] [<000127b697e57180>] __fput+0x2f0/0x880 > [ 153.761579] [<000127b697e58440>] fput_close_sync+0xd0/0x1c0 > [ 153.761583] [<000127b697e4b3f0>] __s390x_sys_close+0x90/0xf0 > [ 153.761586] [<000127b699cdc19e>] __do_syscall+0x1be/0x5a0 > [ 153.761590] [<000127b699d04c7a>] system_call+0x72/0x90 > [ 153.761594] INFO: lockdep is turned off. > > Signed-off-by: Alexandra Winter > --- > drivers/dibs/dibs_loopback.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/dibs/dibs_loopback.c b/drivers/dibs/dibs_loopback.c > index 649e4e375be3..44a2e74c2efc 100644 > --- a/drivers/dibs/dibs_loopback.c > +++ b/drivers/dibs/dibs_loopback.c > @@ -238,6 +238,7 @@ static int dibs_lo_move_data(struct dibs_dev *dibs, u64 dmb_tok, > { > struct dibs_lo_dmb_node *rmb_node = NULL, *tmp_node; > struct dibs_lo_dev *ldev; > + unsigned long flags; > u16 s_mask; > u8 client_id; > u32 sba_idx; > @@ -267,12 +268,12 @@ static int dibs_lo_move_data(struct dibs_dev *dibs, u64 dmb_tok, > if (!sf) > return 0; > > - spin_lock(&dibs->lock); > + spin_lock_irqsave(&dibs->lock, flags); > client_id = dibs->dmb_clientid_arr[sba_idx]; > s_mask = ror16(0x1000, idx); > if (likely(client_id != NO_DIBS_CLIENT && dibs->subs[client_id])) > dibs->subs[client_id]->ops->handle_irq(dibs, sba_idx, s_mask); > - spin_unlock(&dibs->lock); > + spin_unlock_irqrestore(&dibs->lock, flags); > > return 0; > } Reviewed-by: Sidraya Jayagond