CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2023-52490 – mm: migrate: fix getting incorrect page mapping during page migration
https://notcve.org/view.php?id=CVE-2023-52490
In the Linux kernel, the following vulnerability has been resolved: mm: migrate: fix getting incorrect page mapping during page migration When running stress-ng testing, we found below kernel crash after a few hours: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 pc : dentry_name+0xd8/0x224 lr : pointer+0x22c/0x370 sp : ffff800025f134c0 ...... Call trace: dentry_name+0xd8/0x224 pointer+0x22c/0x370 vsnprintf+0x1ec/0x730 vscnprintf+0x2c/0x60 vprintk_store+0x70/0x234 vprintk_emit+0xe0/0x24c vprintk_default+0x3c/0x44 vprintk_func+0x84/0x2d0 printk+0x64/0x88 __dump_page+0x52c/0x530 dump_page+0x14/0x20 set_migratetype_isolate+0x110/0x224 start_isolate_page_range+0xc4/0x20c offline_pages+0x124/0x474 memory_block_offline+0x44/0xf4 memory_subsys_offline+0x3c/0x70 device_offline+0xf0/0x120 ...... After analyzing the vmcore, I found this issue is caused by page migration. The scenario is that, one thread is doing page migration, and we will use the target page's ->mapping field to save 'anon_vma' pointer between page unmap and page move, and now the target page is locked and refcount is 1. Currently, there is another stress-ng thread performing memory hotplug, attempting to offline the target page that is being migrated. It discovers that the refcount of this target page is 1, preventing the offline operation, thus proceeding to dump the page. However, page_mapping() of the target page may return an incorrect file mapping to crash the system in dump_mapping(), since the target page->mapping only saves 'anon_vma' pointer without setting PAGE_MAPPING_ANON flag. There are seveval ways to fix this issue: (1) Setting the PAGE_MAPPING_ANON flag for target page's ->mapping when saving 'anon_vma', but this can confuse PageAnon() for PFN walkers, since the target page has not built mappings yet. (2) Getting the page lock to call page_mapping() in __dump_page() to avoid crashing the system, however, there are still some PFN walkers that call page_mapping() without holding the page lock, such as compaction. (3) Using target page->private field to save the 'anon_vma' pointer and 2 bits page state, just as page->mapping records an anonymous page, which can remove the page_mapping() impact for PFN walkers and also seems a simple way. So I choose option 3 to fix this issue, and this can also fix other potential issues for PFN walkers, such as compaction. En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mm: migrar: se corrigió la asignación de página incorrecta durante la migración de la página Al ejecutar la prueba de estrés, encontramos el siguiente bloqueo del kernel después de unas horas: No se puede manejar la desreferencia del puntero NULL del kernel en virtual dirección 0000000000000000 pc: dentry_name+0xd8/0x224 lr: puntero+0x22c/0x370 sp: ffff800025f134c0 ...... Rastreo de llamadas: dentry_name+0xd8/0x224 puntero+0x22c/0x370 vsnprintf+0x1ec/0x730 vscnprint f+0x2c/0x60 vprintk_store+ 0x70/0x234 vprintk_emit+0xe0/0x24c vprintk_default+0x3c/0x44 vprintk_func+0x84/0x2d0 printk+0x64/0x88 __dump_page+0x52c/0x530 dump_page+0x14/0x20 set_migratetype_isolate+0x110/0x22 4 start_isolate_page_range+0xc4/0x20c offline_pages+0x124/0x474 memoria_block_offline+ 0x44/0xf4 Memory_subsys_offline+0x3c/0x70 device_offline+0xf0/0x120 ...... • https://git.kernel.org/stable/c/64c8902ed4418317cd416c566f896bd4a92b2efc https://git.kernel.org/stable/c/9128bfbc5c80d8f4874dd0a0424d1f5fb010df1b https://git.kernel.org/stable/c/3889a418b6eb9a1113fb989aaadecf2f64964767 https://git.kernel.org/stable/c/d1adb25df7111de83b64655a80b5a135adbded61 •
CVSS: 5.5EPSS: 0%CPEs: 6EXPL: 0CVE-2023-52489 – mm/sparsemem: fix race in accessing memory_section->usage
https://notcve.org/view.php?id=CVE-2023-52489
In the Linux kernel, the following vulnerability has been resolved: mm/sparsemem: fix race in accessing memory_section->usage The below race is observed on a PFN which falls into the device memory region with the system memory configuration where PFN's are such that [ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL]. Since normal zone start and end pfn contains the device memory PFN's as well, the compaction triggered will try on the device memory PFN's too though they end up in NOP(because pfn_to_online_page() returns NULL for ZONE_DEVICE memory sections). When from other core, the section mappings are being removed for the ZONE_DEVICE region, that the PFN in question belongs to, on which compaction is currently being operated is resulting into the kernel crash with CONFIG_SPASEMEM_VMEMAP enabled. The crash logs can be seen at [1]. compact_zone() memunmap_pages ------------- --------------- __pageblock_pfn_to_page ...... (a)pfn_valid(): valid_section()//return true (b)__remove_pages()-> sparse_remove_section()-> section_deactivate(): [Free the array ms->usage and set ms->usage = NULL] pfn_section_valid() [Access ms->usage which is NULL] NOTE: From the above it can be said that the race is reduced to between the pfn_valid()/pfn_section_valid() and the section deactivate with SPASEMEM_VMEMAP enabled. The commit b943f045a9af("mm/sparse: fix kernel crash with pfn_section_valid check") tried to address the same problem by clearing the SECTION_HAS_MEM_MAP with the expectation of valid_section() returns false thus ms->usage is not accessed. Fix this issue by the below steps: a) Clear SECTION_HAS_MEM_MAP before freeing the ->usage. b) RCU protected read side critical section will either return NULL when SECTION_HAS_MEM_MAP is cleared or can successfully access ->usage. c) Free the ->usage with kfree_rcu() and set ms->usage = NULL. No attempt will be made to access ->usage after this as the SECTION_HAS_MEM_MAP is cleared thus valid_section() return false. Thanks to David/Pavan for their inputs on this patch. [1] https://lore.kernel.org/linux-mm/994410bb-89aa-d987-1f50-f514903c55aa@quicinc.com/ On Snapdragon SoC, with the mentioned memory configuration of PFN's as [ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL], we are able to see bunch of issues daily while testing on a device farm. For this particular issue below is the log. • https://git.kernel.org/stable/c/f46edbd1b1516da1fb34c917775168d5df576f78 https://git.kernel.org/stable/c/90ad17575d26874287271127d43ef3c2af876cea https://git.kernel.org/stable/c/b448de2459b6d62a53892487ab18b7d823ff0529 https://git.kernel.org/stable/c/68ed9e33324021e9d6b798e9db00ca3093d2012a https://git.kernel.org/stable/c/70064241f2229f7ba7b9599a98f68d9142e81a97 https://git.kernel.org/stable/c/3a01daace71b521563c38bbbf874e14c3e58adb7 https://git.kernel.org/stable/c/5ec8e8ea8b7783fab150cf86404fc38cb4db8800 https://lists.debian.org/debian-lts-announce/2024/06/ • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •
CVSS: -EPSS: 0%CPEs: 6EXPL: 0CVE-2023-52488 – serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO
https://notcve.org/view.php?id=CVE-2023-52488
In the Linux kernel, the following vulnerability has been resolved: serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO The SC16IS7XX IC supports a burst mode to access the FIFOs where the initial register address is sent ($00), followed by all the FIFO data without having to resend the register address each time. In this mode, the IC doesn't increment the register address for each R/W byte. The regmap_raw_read() and regmap_raw_write() are functions which can perform IO over multiple registers. They are currently used to read/write from/to the FIFO, and although they operate correctly in this burst mode on the SPI bus, they would corrupt the regmap cache if it was not disabled manually. The reason is that when the R/W size is more than 1 byte, these functions assume that the register address is incremented and handle the cache accordingly. Convert FIFO R/W functions to use the regmap _noinc_ versions in order to remove the manual cache control which was a workaround when using the _raw_ versions. FIFO registers are properly declared as volatile so cache will not be used/updated for FIFO accesses. • https://git.kernel.org/stable/c/dfeae619d781dee61666d5551b93ba3be755a86b https://git.kernel.org/stable/c/4e37416e4ee1b1bc17364a68973e0c63be89e611 https://git.kernel.org/stable/c/e635f652696ef6f1230621cfd89c350cb5ec6169 https://git.kernel.org/stable/c/416b10d2817c94db86829fb92ad43ce7d002c573 https://git.kernel.org/stable/c/084c24e788d9cf29c55564de368bf5284f2bb5db https://git.kernel.org/stable/c/aa7cb4787698add9367b19f7afc667662c9bdb23 https://git.kernel.org/stable/c/dbf4ab821804df071c8b566d9813083125e6d97b https://lists.debian.org/debian-lts-announce/2024/06/ •
CVSS: 4.4EPSS: 0%CPEs: 8EXPL: 0CVE-2023-52486 – drm: Don't unref the same fb many times by mistake due to deadlock handling
https://notcve.org/view.php?id=CVE-2023-52486
In the Linux kernel, the following vulnerability has been resolved: drm: Don't unref the same fb many times by mistake due to deadlock handling If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl() we proceed to unref the fb and then retry the whole thing from the top. But we forget to reset the fb pointer back to NULL, and so if we then get another error during the retry, before the fb lookup, we proceed the unref the same fb again without having gotten another reference. The end result is that the fb will (eventually) end up being freed while it's still in use. Reset fb to NULL once we've unreffed it to avoid doing it again until we've done another fb lookup. This turned out to be pretty easy to hit on a DG2 when doing async flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I saw that drm_closefb() simply got stuck in a busy loop while walking the framebuffer list. Fortunately I was able to convince it to oops instead, and from there it was easier to track down the culprit. En el kernel de Linux se ha resuelto la siguiente vulnerabilidad: drm: No desreferenciar el mismo fb muchas veces por error debido al manejo de interbloqueos Si obtenemos un punto muerto después de la búsqueda de fb en drm_mode_page_flip_ioctl() procedemos a desreferenciar el fb y luego Vuelva a intentarlo todo desde arriba. Pero nos olvidamos de restablecer el puntero fb a NULL, por lo que si obtenemos otro error durante el reintento, antes de la búsqueda de fb, procedemos a desref el mismo fb nuevamente sin haber obtenido otra referencia. • https://git.kernel.org/stable/c/376e21a9e4c2c63ee5d8d3aa74be5082c3882229 https://git.kernel.org/stable/c/9dd334a8245011ace45e53298175c7b659edb3e7 https://git.kernel.org/stable/c/f55261469be87c55df13db76dc945f6bcd825105 https://git.kernel.org/stable/c/b4af63da9d94986c529d74499fdfe44289acd551 https://git.kernel.org/stable/c/62f2e79cf9f4f47cc9dea9cebdf58d9f7b5695e0 https://git.kernel.org/stable/c/d7afdf360f4ac142832b098b4de974e867cc063c https://git.kernel.org/stable/c/bfd0feb1b109cb63b87fdcd00122603787c75a1a https://git.kernel.org/stable/c/cb4daf271302d71a6b9a7c01bd0b6d76f • CWE-833: Deadlock •
CVSS: -EPSS: 0%CPEs: 2EXPL: 0CVE-2023-52485 – drm/amd/display: Wake DMCUB before sending a command
https://notcve.org/view.php?id=CVE-2023-52485
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Wake DMCUB before sending a command [Why] We can hang in place trying to send commands when the DMCUB isn't powered on. [How] For functions that execute within a DC context or DC lock we can wrap the direct calls to dm_execute_dmub_cmd/list with code that exits idle power optimizations and reallows once we're done with the command submission on success. For DM direct submissions the DM will need to manage the enter/exit sequencing manually. We cannot invoke a DMCUB command directly within the DM execution helper or we can deadlock. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm/amd/display: activa DMCUB antes de enviar un comando [Por qué] Podemos quedarnos quietos intentando enviar comandos cuando DMCUB no está encendido. [Cómo] Para funciones que se ejecutan dentro de un contexto de DC o bloqueo de DC, podemos ajustar las llamadas directas a dm_execute_dmub_cmd/list con código que salga de las optimizaciones de energía inactivas y se vuelva a permitir una vez que hayamos terminado con el envío del comando en caso de éxito. Para envíos directos de DM, el DM deberá gestionar la secuencia de entrada/salida manualmente. No podemos invocar un comando DMCUB directamente dentro del asistente de ejecución de DM o podemos bloquearnos. • https://git.kernel.org/stable/c/303197775a97416b62d4da69280d0c120a20e009 https://git.kernel.org/stable/c/8892780834ae294bc3697c7d0e056d7743900b39 •