From: Sasha Levin <sashal@kernel.org> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Berg <johannes.berg@intel.com>, Ritesh Raj Sarraf <rrs@debian.org>, Anton Ivanov <anton.ivanov@cambridgegreys.com>, Richard Weinberger <richard@nod.at>, Sasha Levin <sashal@kernel.org>, linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 11/34] um: Mark all kernel symbols as local Date: Wed, 12 May 2021 14:02:42 -0400 [thread overview] Message-ID: <20210512180306.664925-11-sashal@kernel.org> (raw) In-Reply-To: <20210512180306.664925-1-sashal@kernel.org> From: Johannes Berg <johannes.berg@intel.com> [ Upstream commit d5027ca63e0e778b641cf23e3f5c6d6212cf412b ] Ritesh reported a bug [1] against UML, noting that it crashed on startup. The backtrace shows the following (heavily redacted): (gdb) bt ... #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72 ... #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359 ... #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486 #45 0x00007f8990968b85 in __getgrnam_r [...] #46 0x00007f89909d6b77 in grantpt [...] #47 0x00007f8990a9394e in __GI_openpty [...] #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144 indicating that the UML function openpty_cb() calls openpty(), which internally calls __getgrnam_r(), which causes the nsswitch machinery to get started. This loads, through lots of indirection that I snipped, the libcom_err.so.2 library, which (in an unknown function, "??") calls sem_init(). Now, of course it wants to get libpthread's sem_init(), since it's linked against libpthread. However, the dynamic linker looks up that symbol against the binary first, and gets the kernel's sem_init(). Hajime Tazaki noted that "objcopy -L" can localize a symbol, so the dynamic linker wouldn't do the lookup this way. I tried, but for some reason that didn't seem to work. Doing the same thing in the linker script instead does seem to work, though I cannot entirely explain - it *also* works if I just add "VERSION { { global: *; }; }" instead, indicating that something else is happening that I don't really understand. It may be that explicitly doing that marks them with some kind of empty version, and that's different from the default. Explicitly marking them with a version breaks kallsyms, so that doesn't seem to be possible. Marking all the symbols as local seems correct, and does seem to address the issue, so do that. Also do it for static link, nsswitch libraries could still be loaded there. [1] https://bugs.debian.org/983379 Reported-by: Ritesh Raj Sarraf <rrs@debian.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Tested-By: Ritesh Raj Sarraf <rrs@debian.org> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/um/kernel/dyn.lds.S | 6 ++++++ arch/um/kernel/uml.lds.S | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S index dacbfabf66d8..2f2a8ce92f1e 100644 --- a/arch/um/kernel/dyn.lds.S +++ b/arch/um/kernel/dyn.lds.S @@ -6,6 +6,12 @@ OUTPUT_ARCH(ELF_ARCH) ENTRY(_start) jiffies = jiffies_64; +VERSION { + { + local: *; + }; +} + SECTIONS { PROVIDE (__executable_start = START); diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S index 45d957d7004c..7a8e2b123e29 100644 --- a/arch/um/kernel/uml.lds.S +++ b/arch/um/kernel/uml.lds.S @@ -7,6 +7,12 @@ OUTPUT_ARCH(ELF_ARCH) ENTRY(_start) jiffies = jiffies_64; +VERSION { + { + local: *; + }; +} + SECTIONS { /* This must contain the right address - not quite the default ELF one.*/ -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Berg <johannes.berg@intel.com>, Ritesh Raj Sarraf <rrs@debian.org>, Anton Ivanov <anton.ivanov@cambridgegreys.com>, Richard Weinberger <richard@nod.at>, Sasha Levin <sashal@kernel.org>, linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 11/34] um: Mark all kernel symbols as local Date: Wed, 12 May 2021 14:02:42 -0400 [thread overview] Message-ID: <20210512180306.664925-11-sashal@kernel.org> (raw) In-Reply-To: <20210512180306.664925-1-sashal@kernel.org> From: Johannes Berg <johannes.berg@intel.com> [ Upstream commit d5027ca63e0e778b641cf23e3f5c6d6212cf412b ] Ritesh reported a bug [1] against UML, noting that it crashed on startup. The backtrace shows the following (heavily redacted): (gdb) bt ... #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72 ... #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359 ... #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486 #45 0x00007f8990968b85 in __getgrnam_r [...] #46 0x00007f89909d6b77 in grantpt [...] #47 0x00007f8990a9394e in __GI_openpty [...] #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144 indicating that the UML function openpty_cb() calls openpty(), which internally calls __getgrnam_r(), which causes the nsswitch machinery to get started. This loads, through lots of indirection that I snipped, the libcom_err.so.2 library, which (in an unknown function, "??") calls sem_init(). Now, of course it wants to get libpthread's sem_init(), since it's linked against libpthread. However, the dynamic linker looks up that symbol against the binary first, and gets the kernel's sem_init(). Hajime Tazaki noted that "objcopy -L" can localize a symbol, so the dynamic linker wouldn't do the lookup this way. I tried, but for some reason that didn't seem to work. Doing the same thing in the linker script instead does seem to work, though I cannot entirely explain - it *also* works if I just add "VERSION { { global: *; }; }" instead, indicating that something else is happening that I don't really understand. It may be that explicitly doing that marks them with some kind of empty version, and that's different from the default. Explicitly marking them with a version breaks kallsyms, so that doesn't seem to be possible. Marking all the symbols as local seems correct, and does seem to address the issue, so do that. Also do it for static link, nsswitch libraries could still be loaded there. [1] https://bugs.debian.org/983379 Reported-by: Ritesh Raj Sarraf <rrs@debian.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Tested-By: Ritesh Raj Sarraf <rrs@debian.org> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/um/kernel/dyn.lds.S | 6 ++++++ arch/um/kernel/uml.lds.S | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S index dacbfabf66d8..2f2a8ce92f1e 100644 --- a/arch/um/kernel/dyn.lds.S +++ b/arch/um/kernel/dyn.lds.S @@ -6,6 +6,12 @@ OUTPUT_ARCH(ELF_ARCH) ENTRY(_start) jiffies = jiffies_64; +VERSION { + { + local: *; + }; +} + SECTIONS { PROVIDE (__executable_start = START); diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S index 45d957d7004c..7a8e2b123e29 100644 --- a/arch/um/kernel/uml.lds.S +++ b/arch/um/kernel/uml.lds.S @@ -7,6 +7,12 @@ OUTPUT_ARCH(ELF_ARCH) ENTRY(_start) jiffies = jiffies_64; +VERSION { + { + local: *; + }; +} + SECTIONS { /* This must contain the right address - not quite the default ELF one.*/ -- 2.30.2 _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um
next prev parent reply other threads:[~2021-05-12 19:53 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-12 18:02 [PATCH AUTOSEL 5.10 01/34] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6 Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 02/34] PCI: thunder: Fix compile testing Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 03/34] dmaengine: dw-edma: Fix crash on loading/unloading driver Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 04/34] ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend() Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 05/34] f2fs: fix to avoid out-of-bounds memory access Sasha Levin 2021-05-12 18:02 ` [f2fs-dev] " Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 06/34] ACPI / hotplug / PCI: Fix reference count leak in enable_slot() Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 07/34] PCI: tegra: Fix runtime PM imbalance in pex_ep_event_pex_rst_deassert() Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 08/34] Input: elants_i2c - do not bind to i2c-hid compatible ACPI instantiated devices Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 09/34] Input: silead - add workaround for x86 BIOS-es which bring the chip up in a stuck state Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 10/34] NFS: NFS_INO_REVAL_PAGECACHE should mark the change attribute invalid Sasha Levin 2021-05-12 18:02 ` Sasha Levin [this message] 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 11/34] um: Mark all kernel symbols as local Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 12/34] um: Disable CONFIG_GCOV with MODULES Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 13/34] PCI: tegra: Add Tegra194 MCFG quirks for ECAM errata Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 14/34] ARM: 9075/1: kernel: Fix interrupted SMC calls Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 15/34] platform/chrome: cros_ec_typec: Add DP mode check Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 16/34] riscv: Use $(LD) instead of $(CC) to link vDSO Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 17/34] scripts/recordmcount.pl: Fix RISC-V regex for clang Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 18/34] riscv: Workaround mcount name prior to clang-13 Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 19/34] scsi: lpfc: Fix illegal memory access on Abort IOCBs Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 20/34] ceph: fix fscache invalidation Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 21/34] ceph: don't clobber i_snap_caps on non-I_NEW inode Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 22/34] ceph: don't allow access to MDS-private inodes Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 23/34] scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 24/34] amdgpu/pm: Prevent force of DCEFCLK on NAVI10 and SIENNA_CICHLID Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 25/34] bridge: Fix possible races between assigning rx_handler_data and setting IFF_BRIDGE_PORT bit Sasha Levin 2021-05-12 18:02 ` [Bridge] " Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 26/34] net: hsr: check skb can contain struct hsr_ethhdr in fill_frame_info Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 27/34] nvmet: remove unsupported command noise Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` [PATCH AUTOSEL 5.10 28/34] drm/amd/display: Fix two cursor duplication when using overlay Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:02 ` Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 29/34] gpiolib: acpi: Add quirk to ignore EC wakeups on Dell Venue 10 Pro 5055 Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 30/34] net:CXGB4: fix leak if sk_buff is not used Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 31/34] ALSA: hda: generic: change the DAC ctl name for LO+SPK or LO+HP Sasha Levin 2021-05-12 18:03 ` Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 32/34] block: reexpand iov_iter after read/write Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 33/34] lib: stackdepot: turn depot_lock spinlock to raw_spinlock Sasha Levin 2021-05-12 18:03 ` [PATCH AUTOSEL 5.10 34/34] net: stmmac: Do not enable RX FIFO overflow interrupts Sasha Levin 2021-05-12 18:03 ` Sasha Levin
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