December 2017 - Linux-stable-mirror

[Linux-stable-mirror] patch "iio: adc: cpcap: fix incorrect validation" added to staging-linus

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled iio: adc: cpcap: fix incorrect validation to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 81b039ec36a41a5451e1e36f05bb055eceab1dc8 Mon Sep 17 00:00:00 2001 From: Pan Bian <bianpan2016(a)163.com> Date: Mon, 13 Nov 2017 00:01:20 +0800 Subject: iio: adc: cpcap: fix incorrect validation Function platform_get_irq_byname() returns a negative error code on failure, and a zero or positive number on success. However, in function cpcap_adc_probe(), positive IRQ numbers are also taken as error cases. Use "if (ddata->irq < 0)" instead of "if (!ddata->irq)" to validate the return value of platform_get_irq_byname(). Signed-off-by: Pan Bian <bianpan2016(a)163.com> Fixes: 25ec249632d50 ("iio: adc: cpcap: Add minimal support for CPCAP PMIC ADC") Reviewed-by: Sebastian Reichel <sebastian.reichel(a)collabora.co.uk> Acked-by: Tony Lindgren <tony(a)atomide.com> Cc: <Stable(a)vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com> --- drivers/iio/adc/cpcap-adc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iio/adc/cpcap-adc.c b/drivers/iio/adc/cpcap-adc.c index 3576ec73ec23..9ad60421d360 100644 --- a/drivers/iio/adc/cpcap-adc.c +++ b/drivers/iio/adc/cpcap-adc.c @@ -1011,7 +1011,7 @@ static int cpcap_adc_probe(struct platform_device *pdev) platform_set_drvdata(pdev, indio_dev); ddata->irq = platform_get_irq_byname(pdev, "adcdone"); - if (!ddata->irq) + if (ddata->irq < 0) return -ENODEV; error = devm_request_threaded_irq(&pdev->dev, ddata->irq, NULL, -- 2.15.1

6 years, 5 months

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[Linux-stable-mirror] [PATCH 08/10] staging: ccree: NULLify backup_info when unused

by Gilad Ben-Yossef

backup_info field is only allocated for decrypt code path. The field was not nullified when not used causing a kfree in an error handling path to attempt to free random addresses as uncovered in stress testing. Fixes: 737aed947f9b ("staging: ccree: save ciphertext for CTS IV") Cc: stable(a)vger.kernel.org Signed-off-by: Gilad Ben-Yossef <gilad(a)benyossef.com> --- drivers/staging/ccree/ssi_cipher.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/staging/ccree/ssi_cipher.c b/drivers/staging/ccree/ssi_cipher.c index 9019615..7b484f1 100644 --- a/drivers/staging/ccree/ssi_cipher.c +++ b/drivers/staging/ccree/ssi_cipher.c @@ -907,6 +907,7 @@ static int ssi_ablkcipher_encrypt(struct ablkcipher_request *req) unsigned int ivsize = crypto_ablkcipher_ivsize(ablk_tfm); req_ctx->is_giv = false; + req_ctx->backup_info = NULL; return ssi_blkcipher_process(tfm, req_ctx, req->dst, req->src, req->nbytes, req->info, ivsize, -- 2.7.4

6 years, 5 months

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Re: [Linux-stable-mirror] [PATCH] MIPS: fix incorrect mem=X@Y handling

by Mathieu Malaterre

On Tue, Sep 5, 2017 at 1:06 PM, Marcin Nowakowski <marcin.nowakowski(a)imgtec.com> wrote: > Change 73fbc1eba7ff added a fix to ensure that the memory range between > PHYS_OFFSET and low memory address specified by mem= cmdline argument is > not later processed by free_all_bootmem. > This change was incorrect for systems where the commandline specifies > more than 1 mem argument, as it will cause all memory between > PHYS_OFFSET and each of the memory offsets to be marked as reserved, > which results in parts of the RAM marked as reserved (Creator CI20's > u-boot has a default commandline argument 'mem=256M@0x0 > mem=768M@0x30000000'). > > Change the behaviour to ensure that only the range between PHYS_OFFSET > and the lowest start address of the memories is marked as protected. > > This change also ensures that the range is marked protected even if it's > only defined through the devicetree and not only via commandline > arguments. > > Reported-by: Mathieu Malaterre <mathieu.malaterre(a)gmail.com> > Signed-off-by: Marcin Nowakowski <marcin.nowakowski(a)imgtec.com> > Fixes: 73fbc1eba7ff ("MIPS: fix mem=X@Y commandline processing") > Cc: stable(a)vger.kernel.org > --- > arch/mips/kernel/setup.c | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index fe39397..a1c39ec 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -374,6 +374,7 @@ static void __init bootmem_init(void) > unsigned long reserved_end; > unsigned long mapstart = ~0UL; > unsigned long bootmap_size; > + phys_addr_t ramstart = ~0UL; > bool bootmap_valid = false; > int i; > > @@ -394,6 +395,21 @@ static void __init bootmem_init(void) > max_low_pfn = 0; > > /* > + * Reserve any memory between the start of RAM and PHYS_OFFSET > + */ > + for (i = 0; i < boot_mem_map.nr_map; i++) { > + if (boot_mem_map.map[i].type != BOOT_MEM_RAM) > + continue; > + > + ramstart = min(ramstart, boot_mem_map.map[i].addr); > + } > + > + if (ramstart > PHYS_OFFSET) > + add_memory_region(PHYS_OFFSET, ramstart - PHYS_OFFSET, > + BOOT_MEM_RESERVED); > + > + > + /* > * Find the highest page frame number we have available. > */ > for (i = 0; i < boot_mem_map.nr_map; i++) { > @@ -663,9 +679,6 @@ static int __init early_parse_mem(char *p) > > add_memory_region(start, size, BOOT_MEM_RAM); > > - if (start && start > PHYS_OFFSET) > - add_memory_region(PHYS_OFFSET, start - PHYS_OFFSET, > - BOOT_MEM_RESERVED); > return 0; > } > early_param("mem", early_parse_mem); > -- > 2.7.4 > > Teested-by: Mathieu Malaterre <malat(a)debian.org> Would be nice to have it upstream at some point... Thanks

6 years, 5 months

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[Linux-stable-mirror] [PATCH AUTOSEL for 3.18 01/15] route: also update fnhe_genid when updating a route cache

by alexander.levin＠verizon.com

From: Xin Long <lucien.xin(a)gmail.com> [ Upstream commit cebe84c6190d741045a322f5343f717139993c08 ] Now when ip route flush cache and it turn out all fnhe_genid != genid. If a redirect/pmtu icmp packet comes and the old fnhe is found and all it's members but fnhe_genid will be updated. Then next time when it looks up route and tries to rebind this fnhe to the new dst, the fnhe will be flushed due to fnhe_genid != genid. It causes this redirect/pmtu icmp packet acutally not to be applied. This patch is to also reset fnhe_genid when updating a route cache. Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions") Acked-by: Hannes Frederic Sowa <hannes(a)stressinduktion.org> Signed-off-by: Xin Long <lucien.xin(a)gmail.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Signed-off-by: Sasha Levin <alexander.levin(a)verizon.com> --- net/ipv4/route.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 2fe9459fbe24..a04d29d70e6a 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -622,9 +622,12 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, struct fnhe_hash_bucket *hash; struct fib_nh_exception *fnhe; struct rtable *rt; + u32 genid, hval; unsigned int i; int depth; - u32 hval = fnhe_hashfun(daddr); + + genid = fnhe_genid(dev_net(nh->nh_dev)); + hval = fnhe_hashfun(daddr); spin_lock_bh(&fnhe_lock); @@ -647,6 +650,8 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, } if (fnhe) { + if (fnhe->fnhe_genid != genid) + fnhe->fnhe_genid = genid; if (gw) fnhe->fnhe_gw = gw; if (pmtu) { @@ -671,7 +676,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, fnhe->fnhe_next = hash->chain; rcu_assign_pointer(hash->chain, fnhe); } - fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev)); + fnhe->fnhe_genid = genid; fnhe->fnhe_daddr = daddr; fnhe->fnhe_gw = gw; fnhe->fnhe_pmtu = pmtu; -- 2.11.0

6 years, 5 months

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[Linux-stable-mirror] [PATCH AUTOSEL for 4.4 01/20] kbuild: pkg: use --transform option to prefix paths in tar

by alexander.levin＠verizon.com

From: Masahiro Yamada <yamada.masahiro(a)socionext.com> [ Upstream commit 2dbc644ac62bbcb9ee78e84719953f611be0413d ] For rpm-pkg and deb-pkg, a source tar file is created. All paths in the archive must be prefixed with the base name of the tar so that everything is contained in the directory when you extract it. Currently, scripts/package/Makefile uses a symlink for that, and removes it after the tar is created. If you terminate the build during the tar creation, the symlink is left over. Then, at the next package build, you will see a warning like follows: ln: '.' and 'kernel-4.14.0+/.' are the same file It is possible to fix it by adding -n (--no-dereference) option to the "ln" command, but a cleaner way is to use --transform option of "tar" command. This option is GNU extension, but it should not hurt to use it in the Linux build system. The 'S' flag is needed to exclude symlinks from the path fixup. Without it, symlinks in the kernel are broken. Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com> Signed-off-by: Sasha Levin <alexander.levin(a)verizon.com> --- scripts/package/Makefile | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/scripts/package/Makefile b/scripts/package/Makefile index 493e226356ca..52917fb8e0c5 100644 --- a/scripts/package/Makefile +++ b/scripts/package/Makefile @@ -39,10 +39,9 @@ if test "$(objtree)" != "$(srctree)"; then \ false; \ fi ; \ $(srctree)/scripts/setlocalversion --save-scmversion; \ -ln -sf $(srctree) $(2); \ tar -cz $(RCS_TAR_IGNORE) -f $(2).tar.gz \ - $(addprefix $(2)/,$(TAR_CONTENT) $(3)); \ -rm -f $(2) $(objtree)/.scmversion + --transform 's:^:$(2)/:S' $(TAR_CONTENT) $(3); \ +rm -f $(objtree)/.scmversion # rpm-pkg # --------------------------------------------------------------------------- -- 2.11.0

6 years, 5 months

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[Linux-stable-mirror] [PATCH AUTOSEL for 4.9 01/33] kbuild: pkg: use --transform option to prefix paths in tar

by alexander.levin＠verizon.com

From: Masahiro Yamada <yamada.masahiro(a)socionext.com> [ Upstream commit 2dbc644ac62bbcb9ee78e84719953f611be0413d ] For rpm-pkg and deb-pkg, a source tar file is created. All paths in the archive must be prefixed with the base name of the tar so that everything is contained in the directory when you extract it. Currently, scripts/package/Makefile uses a symlink for that, and removes it after the tar is created. If you terminate the build during the tar creation, the symlink is left over. Then, at the next package build, you will see a warning like follows: ln: '.' and 'kernel-4.14.0+/.' are the same file It is possible to fix it by adding -n (--no-dereference) option to the "ln" command, but a cleaner way is to use --transform option of "tar" command. This option is GNU extension, but it should not hurt to use it in the Linux build system. The 'S' flag is needed to exclude symlinks from the path fixup. Without it, symlinks in the kernel are broken. Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com> Signed-off-by: Sasha Levin <alexander.levin(a)verizon.com> --- scripts/package/Makefile | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/scripts/package/Makefile b/scripts/package/Makefile index 71b4a8af9d4d..7badec3498b8 100644 --- a/scripts/package/Makefile +++ b/scripts/package/Makefile @@ -39,10 +39,9 @@ if test "$(objtree)" != "$(srctree)"; then \ false; \ fi ; \ $(srctree)/scripts/setlocalversion --save-scmversion; \ -ln -sf $(srctree) $(2); \ tar -cz $(RCS_TAR_IGNORE) -f $(2).tar.gz \ - $(addprefix $(2)/,$(TAR_CONTENT) $(3)); \ -rm -f $(2) $(objtree)/.scmversion + --transform 's:^:$(2)/:S' $(TAR_CONTENT) $(3); \ +rm -f $(objtree)/.scmversion # rpm-pkg # --------------------------------------------------------------------------- -- 2.11.0

6 years, 5 months

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[Linux-stable-mirror] [PATCH AUTOSEL for 4.14 01/64] irqchip/qcom: Fix u32 comparison with value less than zero

by alexander.levin＠verizon.com

From: Colin Ian King <colin.king(a)canonical.com> [ Upstream commit e9990d70e8a063a7b894c5cbb99f630a0f41200d ] The comparison of u32 nregs being less than zero is never true since nregs is unsigned. Fix this by making nregs a signed integer. Fixes: f20cc9b00c7b ("irqchip/qcom: Add IRQ combiner driver") Signed-off-by: Colin Ian King <colin.king(a)canonical.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Marc Zyngier <marc.zyngier(a)arm.com> Cc: kernel-janitors(a)vger.kernel.org Cc: Jason Cooper <jason(a)lakedaemon.net> Link: https://lkml.kernel.org/r/20171117183553.2739-1-colin.king@canonical.com Signed-off-by: Sasha Levin <alexander.levin(a)verizon.com> --- drivers/irqchip/qcom-irq-combiner.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/irqchip/qcom-irq-combiner.c b/drivers/irqchip/qcom-irq-combiner.c index 6aa3ea479214..f31265937439 100644 --- a/drivers/irqchip/qcom-irq-combiner.c +++ b/drivers/irqchip/qcom-irq-combiner.c @@ -238,7 +238,7 @@ static int __init combiner_probe(struct platform_device *pdev) { struct combiner *combiner; size_t alloc_sz; - u32 nregs; + int nregs; int err; nregs = count_registers(pdev); -- 2.11.0

6 years, 5 months

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[Linux-stable-mirror] [GIT PULL] commits for Linux 3.18

by alexander.levin＠verizon.com

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hi Greg, Pleae pull commits for Linux 3.18 . I've sent a review request for all commits over a week ago and all comments were addressed. Thanks, Sasha ===== The following changes since commit b42518053ffd221d79cff2df8c0257db88a71334: Linux 3.18.85 (2017-11-30 08:35:56 +0000) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git for-greg/4.14/3.18 for you to fetch changes up to 90cbc83fe2279c1f0b5e94196c27253513405d77: perf test attr: Fix ignored test case result (2017-11-30 17:01:13 -0500) - ---------------------------------------------------------------- Ben Hutchings (1): usbip: tools: Install all headers needed for libusbip development Boshi Wang (1): ima: fix hash algorithm initialization Gustavo A. R. Silva (1): EDAC, sb_edac: Fix missing break in switch Hiromitsu Yamasaki (1): spi: sh-msiof: Fix DMA transfer size check Jibin Xu (1): sysrq : fix Show Regs call trace on ARM Lukas Wunner (1): serial: 8250_fintek: Fix rs485 disablement on invalid ioctl() Masami Hiramatsu (1): kprobes: Use synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=y Thomas Richter (1): perf test attr: Fix ignored test case result arch/Kconfig | 2 +- drivers/edac/sb_edac.c | 1 + drivers/spi/spi-sh-msiof.c | 2 +- drivers/tty/serial/8250/8250_fintek.c | 2 +- drivers/tty/sysrq.c | 9 +++++++-- kernel/kprobes.c | 14 ++++++++------ security/integrity/ima/ima_main.c | 4 ++++ tools/perf/tests/attr.c | 2 +- tools/usb/usbip/Makefile.am | 3 ++- 9 files changed, 26 insertions(+), 13 deletions(-) -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJaIIAGAAoJEN6mb/eXdyzcB/AP/2JM6q4DXlQNiG6gFgU1MAIR N6uwbY9a+RRE/P2sSb0fTx+/f2JTdRhY/NK15y2up+vWxOAzBmqE/NotO0gzaMc1 a+8LkomLf9BS4I/ScRb/iAANUBwWcZNPFHuiYRNGg5y0Ru4uI2C4LNpmNXE6uhWC ia7PjeElSbVZptmMAk1Fdb3A+eYZDwZUvBjf1Zcsjd3QYCS2psa/xQu+uvv4CsNX 1UlGnVqF6hIqrpO1JYgS1vRuGSsSdLiPVrFdVha9Npg6ORtBk6Be6y0vq7uHmvqD x0+iFimMTadSRLPWW5u5CmXsDdhgXb3+5PPl8Bw4krJ7RX9/qWLWmyXJ3pGaZr7U 81LFws1Kt7sG+aDwCSq48rhUnbQAEardI16H9abujM3sCe3b0uboLm8PV9K7JlpZ xiK5lo3U1ia2v1TKUeFS2KhdQtnV0YzHpfIDS9TDQk28kFFtkKDek3x8xM74Z6aa xXtDi4qAJpa/73V9cr9DQM0UuavAk+3QDFEZras8C0dkMqi/DIEvpvZUQrvBMj3t bCldw32ylhtg+xaKPNUO7CXoRoKmE6b2kAed0PJ9sZIXYwoS3PGZnvGUDXDNqOY1 Mad0Mhh8JDiEBtBpEuIQzSVSTRNIeOqGYS1RiCN0oPI0uY/3xWZ7NV2bj+KXAqOe 66nYqLJq2Ai7Dgx4l6Es =eGmn -----END PGP SIGNATURE-----

6 years, 5 months

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[Linux-stable-mirror] Patch "mm, oom_reaper: gather each vma to prevent leaking TLB entry" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled mm, oom_reaper: gather each vma to prevent leaking TLB entry to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: mm-oom_reaper-gather-each-vma-to-prevent-leaking-tlb-entry.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 687cb0884a714ff484d038e9190edc874edcf146 Mon Sep 17 00:00:00 2001 From: Wang Nan <wangnan0(a)huawei.com> Date: Wed, 29 Nov 2017 16:09:58 -0800 Subject: mm, oom_reaper: gather each vma to prevent leaking TLB entry From: Wang Nan <wangnan0(a)huawei.com> commit 687cb0884a714ff484d038e9190edc874edcf146 upstream. tlb_gather_mmu(&tlb, mm, 0, -1) means gathering the whole virtual memory space. In this case, tlb->fullmm is true. Some archs like arm64 doesn't flush TLB when tlb->fullmm is true: commit 5a7862e83000 ("arm64: tlbflush: avoid flushing when fullmm == 1"). Which causes leaking of tlb entries. Will clarifies his patch: "Basically, we tag each address space with an ASID (PCID on x86) which is resident in the TLB. This means we can elide TLB invalidation when pulling down a full mm because we won't ever assign that ASID to another mm without doing TLB invalidation elsewhere (which actually just nukes the whole TLB). I think that means that we could potentially not fault on a kernel uaccess, because we could hit in the TLB" There could be a window between complete_signal() sending IPI to other cores and all threads sharing this mm are really kicked off from cores. In this window, the oom reaper may calls tlb_flush_mmu_tlbonly() to flush TLB then frees pages. However, due to the above problem, the TLB entries are not really flushed on arm64. Other threads are possible to access these pages through TLB entries. Moreover, a copy_to_user() can also write to these pages without generating page fault, causes use-after-free bugs. This patch gathers each vma instead of gathering full vm space. In this case tlb->fullmm is not true. The behavior of oom reaper become similar to munmapping before do_exit, which should be safe for all archs. Link: http://lkml.kernel.org/r/20171107095453.179940-1-wangnan0@huawei.com Fixes: aac453635549 ("mm, oom: introduce oom reaper") Signed-off-by: Wang Nan <wangnan0(a)huawei.com> Acked-by: Michal Hocko <mhocko(a)suse.com> Acked-by: David Rientjes <rientjes(a)google.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: Bob Liu <liubo95(a)huawei.com> Cc: Ingo Molnar <mingo(a)kernel.org> Cc: Roman Gushchin <guro(a)fb.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- mm/oom_kill.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -532,7 +532,6 @@ static bool __oom_reap_task_mm(struct ta */ set_bit(MMF_UNSTABLE, &mm->flags); - tlb_gather_mmu(&tlb, mm, 0, -1); for (vma = mm->mmap ; vma; vma = vma->vm_next) { if (!can_madv_dontneed_vma(vma)) continue; @@ -547,11 +546,13 @@ static bool __oom_reap_task_mm(struct ta * we do not want to block exit_mmap by keeping mm ref * count elevated without a good reason. */ - if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED)) + if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED)) { + tlb_gather_mmu(&tlb, mm, vma->vm_start, vma->vm_end); unmap_page_range(&tlb, vma, vma->vm_start, vma->vm_end, NULL); + tlb_finish_mmu(&tlb, vma->vm_start, vma->vm_end); + } } - tlb_finish_mmu(&tlb, 0, -1); pr_info("oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n", task_pid_nr(tsk), tsk->comm, K(get_mm_counter(mm, MM_ANONPAGES)), Patches currently in stable-queue which might be from wangnan0(a)huawei.com are queue-4.14/mm-oom_reaper-gather-each-vma-to-prevent-leaking-tlb-entry.patch

6 years, 5 months

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[Linux-stable-mirror] Patch "mm, memory_hotplug: do not back off draining pcp free pages from kworker context" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled mm, memory_hotplug: do not back off draining pcp free pages from kworker context to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: mm-memory_hotplug-do-not-back-off-draining-pcp-free-pages-from-kworker-context.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 4b81cb2ff69c8a8e297a147d2eb4d9b5e8d7c435 Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko(a)suse.com> Date: Wed, 29 Nov 2017 16:09:54 -0800 Subject: mm, memory_hotplug: do not back off draining pcp free pages from kworker context From: Michal Hocko <mhocko(a)suse.com> commit 4b81cb2ff69c8a8e297a147d2eb4d9b5e8d7c435 upstream. drain_all_pages backs off when called from a kworker context since commit 0ccce3b92421 ("mm, page_alloc: drain per-cpu pages from workqueue context") because the original IPI based pcp draining has been replaced by a WQ based one and the check wanted to prevent from recursion and inter workers dependencies. This has made some sense at the time because the system WQ has been used and one worker holding the lock could be blocked while waiting for new workers to emerge which can be a problem under OOM conditions. Since then commit ce612879ddc7 ("mm: move pcp and lru-pcp draining into single wq") has moved draining to a dedicated (mm_percpu_wq) WQ with a rescuer so we shouldn't depend on any other WQ activity to make a forward progress so calling drain_all_pages from a worker context is safe as long as this doesn't happen from mm_percpu_wq itself which is not the case because all workers are required to _not_ depend on any MM locks. Why is this a problem in the first place? ACPI driven memory hot-remove (acpi_device_hotplug) is executed from the worker context. We end up calling __offline_pages to free all the pages and that requires both lru_add_drain_all_cpuslocked and drain_all_pages to do their job otherwise we can have dangling pages on pcp lists and fail the offline operation (__test_page_isolated_in_pageblock would see a page with 0 ref count but without PageBuddy set). Fix the issue by removing the worker check in drain_all_pages. lru_add_drain_all_cpuslocked doesn't have this restriction so it works as expected. Link: http://lkml.kernel.org/r/20170828093341.26341-1-mhocko@kernel.org Fixes: 0ccce3b924212 ("mm, page_alloc: drain per-cpu pages from workqueue context") Signed-off-by: Michal Hocko <mhocko(a)suse.com> Cc: Mel Gorman <mgorman(a)suse.de> Cc: Tejun Heo <tj(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- mm/page_alloc.c | 4 ---- 1 file changed, 4 deletions(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2487,10 +2487,6 @@ void drain_all_pages(struct zone *zone) if (WARN_ON_ONCE(!mm_percpu_wq)) return; - /* Workqueues cannot recurse */ - if (current->flags & PF_WQ_WORKER) - return; - /* * Do not drain if one is already in progress unless it's specific to * a zone. Such callers are primarily CMA and memory hotplug and need Patches currently in stable-queue which might be from mhocko(a)suse.com are queue-4.14/mm-oom_reaper-gather-each-vma-to-prevent-leaking-tlb-entry.patch queue-4.14/mm-memory_hotplug-do-not-back-off-draining-pcp-free-pages-from-kworker-context.patch

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Linux-stable-mirror December 2017