From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B129919E839; Sat, 23 May 2026 11:10:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779534620; cv=none; b=TkIL2GxlrMeBTos0QDlo6bMgGmafm1Q5/GIfviTOOvJI/JBlWJogtrWsSaigJJqBPVKBrX6qVzsTDYQIQgs4TxPi/wwwwLwipZ70B8eSQxMOID8vfvx/vrIUayDoCv1YU55Voms7d6t8zimWNZCZL5ktrGGrw6KBCgp1Uqw183o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779534620; c=relaxed/simple; bh=j7p2Hr2ZpFaWMyGnVzhRIAyfeSxci2vr8E2R1PAvaik=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=m91UwoOQZlzwW4Que/ahKpOM9EayoJVvR+YYUx82ybVZeO9QELRxp0bzgLullF9oJCPdontRPTHToab4R8nNrSl9myV4fT2QHbyzCn9JyhShKxHk4DEqkwg+ObPTIrA6vc89iDCyqfkj1Qrgh1679zypU8bHxjkukQ73QVD0Xr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UDN4vGhO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UDN4vGhO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8FA861F000E9; Sat, 23 May 2026 11:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779534619; bh=LAn5/rSg38hc53gW2EUGtGsJLHmmYPjsDrEhurL4oco=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=UDN4vGhOtE76+AVhr2HIPQDDSkz0NvvwtxvwtCiZTnAQXEYPqrkfHVW1CBCmEladV LYWHImgnmMtm0lIDU3GdtrbQTM9UUtY8TdBX02wabi0xtLrLSxWxSonBSktAPK5hQ8 IrhJbhU63dfZCAgbw/PAaq5/W2Ffb+parbM89c6sCx/SI/xwr1OskqYZ7uRe3AkHwk jYBoXqskKCW2ATtjhNYsDMAse94FNepS/Vt2rppfynXdVW0xU5/qnGVbbe9N6UZF2P WT5K2DRqAJkgCTxQyy0l+uX4p9l7B7ka1XmvkAMmqeVQdIjHvV4zosPQgrMhxQoZIl loxD3fO0OfJJg== Message-ID: <4d035995bef0f035eae2b613ed09f02f9920d18a.camel@kernel.org> Subject: Re: [PATCH] NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock From: Jeff Layton To: Michael Bommarito Cc: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Date: Sat, 23 May 2026 07:10:16 -0400 In-Reply-To: References: <20260523014107.2460863-1-michael.bommarito@gmail.com> <8793ba93d173b82bd210a223a91664ee245b66dd.camel@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Sat, 2026-05-23 at 07:02 -0400, Michael Bommarito wrote: > On Sat, May 23, 2026 at 6:55=E2=80=AFAM Jeff Layton = wrote: > > Comment is a bit confusing, given that you replaced > > list_for_each_entry_safe() with list_for_each_entry(). >=20 > Sorry, that's left over from an earlier patch attempt that introduced > a different issue. How would this comment look? >=20 > Concurrent nfsd4_ssc_cancel_dul() can free an item while spinlock is > dropped for mntput() above, so restart the walk from the head so no > stale pointer is followed. Sure, looks good. FWIW, the "restart the loop after dropping the lock" pattern is pretty common across the kernel, but it is good to lay out the rationale in a comment. --=20 Jeff Layton