From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (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 0AE38BA42; Tue, 12 Aug 2025 12:32:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=130.133.4.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755001936; cv=none; b=CqsYNvLu2WzGHHwZj2m5Quhwg9UQOLp8Nyf47LfM6W/peTSvrwNtO+Yls4uSKe0Z6Myqhw3CPBcAD2OIwNJK4JghLk3eOr1GeKGqk9fsvmrC9vS80mL6u1qUF7TOG32sMekrBvOU+bHDYwk2qtohbE8+yqBtbNXtcR3bDSSrcJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755001936; c=relaxed/simple; bh=i7agqy0jRLc9qTaj5262VejUOuXNHO3ToLtIanqt+L4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=gpFayVRHHYNvEdEjU5jhCx1xZsTlMxI7DCYGGu5HejIhJ+qyE0acuUErZAKOYjMDRrcAkLk/lJRqLWu/gCFSGRJKQ6e0sRFpwSJoIVHQf1X4WJTPmiAwMEAkDdtWN5xsFRRE9Pyo9Mgane249Fw122VoC2TfYWE8QH7XS6eZ+XQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de; spf=pass smtp.mailfrom=zedat.fu-berlin.de; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b=iqVf8XdA; arc=none smtp.client-ip=130.133.4.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zedat.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b="iqVf8XdA" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fu-berlin.de; s=fub01; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:From: Reply-To:Subject:Date:Message-ID:To:Cc:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:In-Reply-To: References; bh=SKpmHN01KC7pVvUtH9iyAqSxr6fKMpFvxo6MLypQMa8=; t=1755001932; x=1755606732; b=iqVf8XdA4h8QhbKUNJhUV400XwooJTD6bKVFBPbm7eYLLQD4msUsWK6audjUh uGeHPvYkAcqKEdd33l+cDetVMpX6Wnji9geCAZQi93RCEbhlPZ2ULEuCGemk0J44lm78P45LNW6iW YdcHSj49jUZy30Yn032UfNdArpS/dtW8LixQWYkSGa+11h+UFpXYeMm+ngEmKyToXTOFK7brnwr9L fj/fUK5cwJdzVFAUvFoe9EbN6pxz+bLQcA/hxkYUAGPHsz2UULxXqqu8o7uPCeULkydZ/DKGsHT8m qfbp/q0hN+/a5CXBnujQqsDBC2niGLir5u10I+uaLiIYQvJz+g==; Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.98) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1uloAb-00000000B0L-3dvc; Tue, 12 Aug 2025 14:32:01 +0200 Received: from p57bd96d0.dip0.t-ipconnect.de ([87.189.150.208] helo=[192.168.178.61]) by inpost2.zedat.fu-berlin.de (Exim 4.98) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1uloAb-00000002oi6-2XDR; Tue, 12 Aug 2025 14:32:01 +0200 Message-ID: Subject: Found it - was: Re: [PATCH] sparc64: fix hugetlb for sun4u From: John Paul Adrian Glaubitz To: Anthony Yznaga , sparclinux@vger.kernel.org, davem@davemloft.net, andreas@gaisler.com Cc: linux-kernel@vger.kernel.org, agordeev@linux.ibm.com, will@kernel.org, ryan.roberts@arm.com, david@redhat.com, osalvador@suse.de, Meelis Roos Date: Tue, 12 Aug 2025 14:32:00 +0200 In-Reply-To: <2daaa0648e9bcca42bf7a76d90580725f44fb4bc.camel@physik.fu-berlin.de> References: <20250716012446.10357-1-anthony.yznaga@oracle.com> <35f5ec4eda8a7dbeeb7df9ec0be5c0b062c509f7.camel@physik.fu-berlin.de> <7e1e9aa5-0529-4fb5-84fb-557b5cc1cd50@oracle.com> <38f4469f48e6d36fa92b445c8ecef7a440be43e6.camel@physik.fu-berlin.de> <2bcb018c8b237f7ab2356f4459e14ae81a6fec8b.camel@physik.fu-berlin.de> <2daaa0648e9bcca42bf7a76d90580725f44fb4bc.camel@physik.fu-berlin.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-ZEDAT-Hint: PO Hi Anthony, On Mon, 2025-08-11 at 12:44 +0200, John Paul Adrian Glaubitz wrote: > Hi, >=20 > On Mon, 2025-08-11 at 00:20 +0200, John Paul Adrian Glaubitz wrote: > > Hi, > >=20 > > On Sun, 2025-08-10 at 11:52 +0200, John Paul Adrian Glaubitz wrote: > > > On Sat, 2025-08-09 at 08:42 +0200, John Paul Adrian Glaubitz wrote: > > > > Let me know if you have more suggestions to test. I can also provid= e you with full > > > > access to this Netra 240 if you send me your public SSH key in a pr= ivate mail. > > >=20 > > > I have narrowed it down to a regression between v6.3 and v6.4 now. > > >=20 > > > The bug can be reproduced with the sparc64_defconfig on a Sun Netra 2= 40 by setting > > > CONFIG_TRANSPARENT_HUGEPAGE=3Dy and CONFIG_TRANSPARENT_HUGEPAGE_ALWAY= S=3Dy. When testing > > > on a modern systemd-based distribution, it's also necessary to enable= CGroup support > > > as well as enable support for Sun partition tables with CONFIG_SUN_PA= RTITION=3Dy. > > >=20 > > > Then it should be a matter of bisecting the commits between v6.3 and = v6.4. > > >=20 > > > I will do that within the next days as I'm currently a bit busy with = other stuff. > >=20 > > OK, it turns out it's reproducible on older kernels (but not as old as = 4.19) as well. > > It's just much harder to trigger. I found a reproducer though and will = try to find > > the problematic commit next. > >=20 > > [50686.808389] BUG: Bad page map in process sshd-session pte:00000002 = pmd:01448000 > > [50686.905701] addr:00000100000a0000 vm_flags:00000075 anon_vma:0000000= 000000000 mapping:fff000003c8ca4f8 index:50 > > [50687.038425] file:sshd-session fault:filemap_fault mmap:ext4_file_mma= p [ext4] read_folio:ext4_read_folio [ext4] > > [50687.170246] CPU: 0 PID: 37883 Comm: sshd-session Not tainted 6.3.0-2= -sparc64 #1 Debian 6.3.11-1 > > [50687.285751] Call Trace: > > [50687.317771] [<0000000000d660b0>] dump_stack+0x8/0x18 > > [50687.382976] [<000000000064fd1c>] print_bad_pte+0x15c/0x200 > > [50687.455024] [<0000000000650f84>] unmap_page_range+0x3e4/0xbe0 > > [50687.530513] [<0000000000651cd8>] unmap_vmas+0xf8/0x1a0 > > [50687.597993] [<000000000065e674>] exit_mmap+0xb4/0x360 > > [50687.664331] [<00000000004647dc>] __mmput+0x3c/0x120 > > [50687.728380] [<00000000004648f4>] mmput+0x34/0x60 > > [50687.788999] [<000000000046b510>] do_exit+0x250/0xa00 > > [50687.854194] [<000000000046bea4>] do_group_exit+0x24/0xa0 > > [50687.923962] [<000000000046bf3c>] sys_exit_group+0x1c/0x40 > > [50687.994875] [<0000000000406174>] linux_sparc_syscall+0x34/0x44 > > [50688.071518] Disabling lock debugging due to kernel taint > > [50689.484196] Unable to handle kernel paging request at virtual addres= s 000c000002400000 > > [50689.588368] tsk->{mm,active_mm}->context =3D 00000000001815a6 > > [50689.661677] tsk->{mm,active_mm}->pgd =3D fff000000ae60000 > > [50689.730374] \|/ ____ \|/ > > "@'/ .. \`@" > > /_| \__/ |_\ > > \__U_/ > > [50689.923679] sshd-session(37883): Oops [#1] > > [50689.977420] CPU: 0 PID: 37883 Comm: sshd-session Tainted: G B = 6.3.0-2-sparc64 #1 Debian 6.3.11-1 > > [50690.112384] TSTATE: 0000008811001607 TPC: 00000000006510cc TNPC: 000= 00000006510d0 Y: 00000000 Tainted: G B =20 > > [50690.261089] TPC: > > [50690.320650] g0: 00000000000004a8 g1: 000c000000000000 g2: 0000000000= 008800 g3: ffffffffffffffff > > [50690.435029] g4: fff0000001ef1280 g5: 0000000031200000 g6: fff0000001= f04000 g7: ffffffffffffffff > > [50690.549403] o0: 000c000002400a20 o1: 00000100000a4000 o2: 0000000100= 048290 o3: 0000000000000000 > > [50690.663779] o4: 0000000000000001 o5: 000000000000000d sp: fff0000001= f06f61 ret_pc: 0000010000000000 > > [50690.782728] RPC: <0x10000000000> > > [50690.825039] l0: 0000000100048290 l1: 000c000002400a20 l2: 0000010000= 0a6000 l3: fff0000000950000 > > [50690.939419] l4: 00000100000fc000 l5: fff000000196dc20 l6: fff0000001= f07938 l7: 00000000010f6fd0 > > [50691.053798] i0: fff0000001f07aa8 i1: 0000000000002000 i2: 0000010000= 0a4000 i3: fff0000008311b00 > > [50691.168170] i4: 0000000000100000 i5: fff0000001448290 i6: fff0000001= f07081 i7: 0000000000651cd8 > > [50691.282546] I7: > > [50691.332867] Call Trace: > > [50691.364891] [<0000000000651cd8>] unmap_vmas+0xf8/0x1a0 > > [50691.432371] [<000000000065e674>] exit_mmap+0xb4/0x360 > > [50691.498708] [<00000000004647dc>] __mmput+0x3c/0x120 > > [50691.562759] [<00000000004648f4>] mmput+0x34/0x60 > > [50691.623376] [<000000000046b510>] do_exit+0x250/0xa00 > > [50691.688573] [<000000000046bea4>] do_group_exit+0x24/0xa0 > > [50691.758340] [<000000000046bf3c>] sys_exit_group+0x1c/0x40 > > [50691.829256] [<0000000000406174>] linux_sparc_syscall+0x34/0x44 > > [50691.905886] Caller[0000000000651cd8]: unmap_vmas+0xf8/0x1a0 > > [50691.979085] Caller[000000000065e674]: exit_mmap+0xb4/0x360 > > [50692.051141] Caller[00000000004647dc]: __mmput+0x3c/0x120 > > [50692.120911] Caller[00000000004648f4]: mmput+0x34/0x60 > > [50692.187246] Caller[000000000046b510]: do_exit+0x250/0xa00 > > [50692.258160] Caller[000000000046bea4]: do_group_exit+0x24/0xa0 > > [50692.333645] Caller[000000000046bf3c]: sys_exit_group+0x1c/0x40 > > [50692.410280] Caller[0000000000406174]: linux_sparc_syscall+0x34/0x44 > > [50692.492629] Caller[fff0000102ad4a74]: 0xfff0000102ad4a74 > > [50692.562397] Instruction DUMP: > > [50692.562399] ce762010=20 > > [50692.601281] 02f47fa8=20 > > [50692.632163] c4362018=20 > > [50692.663044] > > [50692.693926] 86100011=20 > > [50692.724808] 8e08a001=20 > > [50692.755689] 8400bfff=20 > > [50692.786569] 8779d402=20 > > [50692.817451] c458e018=20 > >=20 > > [50692.898656] Fixing recursive fault but reboot is needed! >=20 > So, I was able now to even reproduce it in kernel versions as early as 5.= 2: >=20 > [ 122.085803] Unable to handle kernel NULL pointer dereference > [ 122.160227] tsk->{mm,active_mm}->context =3D 000000000000009d > [ 122.233502] tsk->{mm,active_mm}->pgd =3D fff0000231d14000 > [ 122.302118] \|/ ____ \|/ > [ 122.302118] "@'/ .. \`@" > [ 122.302118] /_| \__/ |_\ > [ 122.302118] \__U_/ > [ 122.495420] systemd(1): Oops [#1] > [ 122.538874] CPU: 0 PID: 1 Comm: systemd Not tainted 5.2.0-3-sparc64 #1= Debian 5.2.17-1 > [ 122.642957] TSTATE: 0000004411001601 TPC: 000000000061cd94 TNPC: 00000= 0000061cd98 Y: 00000000 Not tainted > [ 122.772207] TPC: > [ 122.830529] g0: 0000000000000000 g1: 00000000000007ff g2: 000000000000= 0000 g3: 00000000000007df > [ 122.944902] g4: fff00002381771c0 g5: 0000000000000003 g6: fff000023817= 8000 g7: 0000000000000000 > [ 123.059275] o0: fff000023817be18 o1: 0000000000000000 o2: 000000000000= 0000 o3: fff000023817be18 > [ 123.173658] o4: 0000000000000000 o5: 0000000000000000 sp: fff000023817= b341 ret_pc: 000000000061cd7c > [ 123.292611] RPC: > [ 123.350933] l0: 0000010000204010 l1: fff0000101600e28 l2: e4e45b5b8ae4= 4628 l3: 0000000000000000 > [ 123.465311] l4: 0000000000000000 l5: 0000000000000000 l6: 000000000000= 0000 l7: fff0000100bff140 > [ 123.579692] i0: fff000023817bd50 i1: fff000023817be18 i2: 000000000000= 0001 i3: 0000000000000900 > [ 123.694060] i4: 0000000000000000 i5: fff00002320c1210 i6: fff000023817= b3f1 i7: 000000000061ce48 > [ 123.808439] I7: > [ 123.858759] Call Trace: > [ 123.890785] [000000000061ce48] vfs_getattr+0x28/0x40 > [ 123.957123] [000000000061cf64] vfs_statx+0x84/0xc0 > [ 124.021173] [000000000061d918] sys_statx+0x38/0x60 > [ 124.085226] [0000000000406154] linux_sparc_syscall+0x34/0x44 > [ 124.160708] Disabling lock debugging due to kernel taint > [ 124.230481] Caller[000000000061ce48]: vfs_getattr+0x28/0x40 > [ 124.303680] Caller[000000000061cf64]: vfs_statx+0x84/0xc0 > [ 124.374593] Caller[000000000061d918]: sys_statx+0x38/0x60 > [ 124.445503] Caller[0000000000406154]: linux_sparc_syscall+0x34/0x44 > [ 124.527857] Caller[fff00001013fde40]: 0xfff00001013fde40 > [ 124.597621] Instruction DUMP: > [ 124.597623] c2264000=20 > [ 124.636505] 861027df=20 > [ 124.667386] c45f6028=20 > [ 124.698267] > [ 124.729148] 8408a401=20 > [ 124.760031] 83789403=20 > [ 124.790910] c2264000=20 > [ 124.821801] c207600c=20 > [ 124.852675] 80886800=20 > [ 124.883556]=20 > [ 124.954015] Kernel panic - not syncing: Attempted to kill init! exitco= de=3D0x00000009 > [ 125.054721] Press Stop-A (L1-A) from sun keyboard or send break > [ 125.054721] twice on console to return to the boot prom > [ 125.201103] ---[ end Kernel panic - not syncing: Attempted to kill ini= t! exitcode=3D0x00000009 ]--- >=20 > On v5.6, I'm getting an interesting error mentioning D-cache parity error= s: >=20 > [ 125.743109] CPU[0]: Cheetah+ D-cache parity error at TPC[000000000056b= acc] > [ 125.833511] TPC > [ 127.909612] systemd-sysv-generator[1677]: SysV service '/etc/init.d/bu= ildd' lacks a native systemd unit file, automatically generating a unit fil= e for compatibility. > [ 128.104239] systemd-sysv-generator[1677]: Please update package to inc= lude a native systemd unit file. > [ 128.227312] systemd-sysv-generator[1677]: =E2=9A=A0 This compatibility= logic is deprecated, expect removal soon. =E2=9A=A0 > [ 129.638144] Unable to handle kernel NULL pointer dereference > [ 129.712528] tsk->{mm,active_mm}->context =3D 000000000000009e > [ 129.785808] tsk->{mm,active_mm}->pgd =3D fff0000233d38000 > [ 129.854522] \|/ ____ \|/ > [ 129.854522] "@'/ .. \`@" > [ 129.854522] /_| \__/ |_\ > [ 129.854522] \__U_/ > [ 130.047827] systemd(1): Oops [#1] > [ 130.091278] CPU: 0 PID: 1 Comm: systemd Tainted: G E 5.= 6.0-2-sparc64 #1 Debian 5.6.14-2 > [ 130.213664] TSTATE: 0000009911001604 TPC: 00000000005506d8 TNPC: 00000= 000005506dc Y: 00000000 Tainted: G E =20 > [ 130.361222] TPC: > [ 130.418486] g0: 0000000002000000 g1: 0000000000000000 g2: 000000000000= 0000 g3: 0000000000000002 > [ 130.532867] g4: fff000023c178000 g5: 0000000000657300 g6: fff000023c18= 0000 g7: fff000023423e684 > [ 130.647245] o0: ffffffff00002000 o1: 0000000000000001 o2: fff000023416= 8fa0 o3: 0000000000000000 > [ 130.761617] o4: fff0000237761f80 o5: 0000000000000001 sp: fff000023c18= 2fd1 ret_pc: 00000000005f2c84 > [ 130.880576] RPC: <__vfree+0x24/0x80> > [ 130.927456] l0: ffffffffffffffff l1: 0000000000000001 l2: 000000000000= 0400 l3: 0000000002000000 > [ 131.041836] l4: 0000000000debc00 l5: 0000000000000100 l6: 000000000000= 0001 l7: fff000023c005e40 > [ 131.156213] i0: 000000010004e000 i1: 0000000000002000 i2: 000000000010= 0cc0 i3: fff0000237761300 > [ 131.270589] i4: 0000000000000001 i5: 0000000000000001 i6: fff000023c18= 3081 i7: 0000000000550a70 > [ 131.384963] I7: > [ 131.447862] Call Trace: > [ 131.479889] [0000000000550a70] bpf_patch_insn_single+0x70/0x1e0 > [ 131.558814] [000000000055fe58] bpf_patch_insn_data+0x18/0x1c0 > [ 131.635442] [000000000056bed8] bpf_check+0x1cf8/0x3060 > [ 131.704064] [0000000000559778] bpf_prog_load+0x498/0x8e0 > [ 131.774975] [0000000000559d10] __do_sys_bpf+0x150/0x1880 > [ 131.845890] [000000000055b534] sys_bpf+0x14/0x560 > [ 131.908807] [0000000000406154] linux_sparc_syscall+0x34/0x44 > [ 131.984281] Disabling lock debugging due to kernel taint > [ 132.054051] Caller[0000000000550a70]: bpf_patch_insn_single+0x70/0x1e0 > [ 132.139832] Caller[000000000055fe58]: bpf_patch_insn_data+0x18/0x1c0 > [ 132.223325] Caller[000000000056bed8]: bpf_check+0x1cf8/0x3060 > [ 132.298811] Caller[0000000000559778]: bpf_prog_load+0x498/0x8e0 > [ 132.376588] Caller[0000000000559d10]: __do_sys_bpf+0x150/0x1880 > [ 132.454361] Caller[000000000055b534]: sys_bpf+0x14/0x560 > [ 132.524132] Caller[0000000000406154]: linux_sparc_syscall+0x34/0x44 > [ 132.606483] Caller[fff0000100995b38]: 0xfff0000100995b38 > [ 132.676247] Instruction DUMP: > [ 132.676249] c25e2020=20 > [ 132.715134] 92270009=20 > [ 132.746014] bb326000=20 > [ 132.776895] > [ 132.807776] 400021a1=20 > [ 132.838657] 9210001d=20 > [ 132.869540] 80a22000=20 > [ 132.900422] 12400016=20 > [ 132.931303] 03003480=20 > [ 132.962184]=20 > [ 133.020246] systemd-journald[205]: Time jumped backwards, rotating. (D= ropped 1 similar message(s)) > [ 133.138938] Kernel panic - not syncing: Attempted to kill init! exitco= de=3D0x00000009 > [ 133.239608] Press Stop-A (L1-A) from sun keyboard or send break > [ 133.239608] twice on console to return to the boot prom > [ 133.385997] ---[ end Kernel panic - not syncing: Attempted to kill ini= t! exitcode=3D0x00000009 ]--- >=20 > Searching for that error in the archives, yielded this report from 2018 [= 1] which seems to have never > been addressed by David Miller. >=20 > @Anthony: Can you see any suspicious in the disassembled code that Meelis= (CC'ed) posted? OK, bisecting has lead me to the following commit: d53d2f78ceadba081fc7785570798c3c8d50a718 is the first bad commit commit d53d2f78ceadba081fc7785570798c3c8d50a718 (HEAD) Author: Rick Edgecombe Date: Thu Apr 25 17:11:38 2019 -0700 bpf: Use vmalloc special flag =20 Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set R= W before freeing which is no longer needed. Don't track if the memory is = RO anymore because it is now tracked in vmalloc. =20 Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Daniel Borkmann Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Nadav Amit Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-19-namit@vmware.com Signed-off-by: Ingo Molnar include/linux/filter.h | 17 +++-------------- kernel/bpf/core.c | 1 - 2 files changed, 3 insertions(+), 15 deletions(-) I assume it's also related to this change: commit 868b104d7379e28013e9d48bdd2db25e0bdcf751 Author: Rick Edgecombe Date: Thu Apr 25 17:11:36 2019 -0700 mm/vmalloc: Add flag for freeing of special permsissions =20 Add a new flag VM_FLUSH_RESET_PERMS, for enabling vfree operations to immediately clear executable TLB entries before freeing pages, and hand= le resetting permissions on the directmap. This flag is useful for any kin= d of memory with elevated permissions, or where there can be related permissions changes on the directmap. Today this is RO+X and RO memory. =20 Although this enables directly vfreeing non-writeable memory now, non-writable memory cannot be freed in an interrupt because the allocat= ion itself is used as a node on deferred free list. So when RO memory needs= to be freed in an interrupt the code doing the vfree needs to have its own work queue, as was the case before the deferred vfree list was added to vmalloc. =20 For architectures with set_direct_map_ implementations this whole opera= tion can be done with one TLB flush when centralized like this. For others w= ith directmap permissions, currently only arm64, a backup method using set_memory functions is used to reset the directmap. When arm64 adds set_direct_map_ functions, this backup can be removed. =20 When the TLB is flushed to both remove TLB entries for the vmalloc rang= e mapping and the direct map permissions, the lazy purge operation could = be done to try to save a TLB flush later. However today vm_unmap_aliases could flush a TLB range that does not include the directmap. So a helpe= r is added with extra parameters that can allow both the vmalloc address = and the direct mapping to be flushed during this operation. The behavior of= the normal vm_unmap_aliases function is unchanged. =20 Suggested-by: Dave Hansen Suggested-by: Andy Lutomirski Suggested-by: Will Deacon Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Cc: Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Nadav Amit Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-17-namit@vmware.com Signed-off-by: Ingo Molnar Adrian --=20 .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913