{"api_version":"1","generated_at":"2026-08-18T07:56:22+00:00","cve":"CVE-2024-46687","urls":{"html":"https://cve.report/CVE-2024-46687","api":"https://cve.report/api/cve/CVE-2024-46687.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2024-46687","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-46687"},"summary":{"title":"btrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk()\n\n[BUG]\nThere is an internal report that KASAN is reporting use-after-free, with\nthe following backtrace:\n\n  BUG: KASAN: slab-use-after-free in btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n  Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45\n  CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014\n  Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]\n  Call Trace:\n   dump_stack_lvl+0x61/0x80\n   print_address_description.constprop.0+0x5e/0x2f0\n   print_report+0x118/0x216\n   kasan_report+0x11d/0x1f0\n   btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n   process_one_work+0xce0/0x12a0\n   worker_thread+0x717/0x1250\n   kthread+0x2e3/0x3c0\n   ret_from_fork+0x2d/0x70\n   ret_from_fork_asm+0x11/0x20\n\n  Allocated by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   __kasan_slab_alloc+0x7d/0x80\n   kmem_cache_alloc_noprof+0x16e/0x3e0\n   mempool_alloc_noprof+0x12e/0x310\n   bio_alloc_bioset+0x3f0/0x7a0\n   btrfs_bio_alloc+0x2e/0x50 [btrfs]\n   submit_extent_page+0x4d1/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n  Freed by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   kasan_save_free_info+0x37/0x50\n   __kasan_slab_free+0x4b/0x60\n   kmem_cache_free+0x214/0x5d0\n   bio_free+0xed/0x180\n   end_bbio_data_read+0x1cc/0x580 [btrfs]\n   btrfs_submit_chunk+0x98d/0x1880 [btrfs]\n   btrfs_submit_bio+0x33/0x70 [btrfs]\n   submit_one_bio+0xd4/0x130 [btrfs]\n   submit_extent_page+0x3ea/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n[CAUSE]\nAlthough I cannot reproduce the error, the report itself is good enough\nto pin down the cause.\n\nThe call trace is the regular endio workqueue context, but the\nfree-by-task trace is showing that during btrfs_submit_chunk() we\nalready hit a critical error, and is calling btrfs_bio_end_io() to error\nout.  And the original endio function called bio_put() to free the whole\nbio.\n\nThis means a double freeing thus causing use-after-free, e.g.:\n\n1. Enter btrfs_submit_bio() with a read bio\n   The read bio length is 128K, crossing two 64K stripes.\n\n2. The first run of btrfs_submit_chunk()\n\n2.1 Call btrfs_map_block(), which returns 64K\n2.2 Call btrfs_split_bio()\n    Now there are two bios, one referring to the first 64K, the other\n    referring to the second 64K.\n2.3 The first half is submitted.\n\n3. The second run of btrfs_submit_chunk()\n\n3.1 Call btrfs_map_block(), which by somehow failed\n    Now we call btrfs_bio_end_io() to handle the error\n\n3.2 btrfs_bio_end_io() calls the original endio function\n    Which is end_bbio_data_read(), and it calls bio_put() for the\n    original bio.\n\n    Now the original bio is freed.\n\n4. The submitted first 64K bio finished\n   Now we call into btrfs_check_read_bio() and tries to advance the bio\n   iter.\n   But since the original bio (thus its iter) is already freed, we\n   trigger the above use-after free.\n\n   And even if the memory is not poisoned/corrupted, we will later call\n   the original endio function, causing a double freeing.\n\n[FIX]\nInstead of calling btrfs_bio_end_io(), call btrfs_orig_bbio_end_io(),\nwhich has the extra check on split bios and do the pr\n---truncated---","state":"PUBLISHED","assigner":"Linux","published_at":"2024-09-13 06:15:13","updated_at":"2026-08-04 11:20:15"},"problem_types":["CWE-415","CWE-416"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/51722b99f41f5e722ffa10b8f61e802a0e70b331","name":"https://git.kernel.org/stable/c/51722b99f41f5e722ffa10b8f61e802a0e70b331","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/10d9d8c3512f16cad47b2ff81ec6fc4b27d8ee10","name":"https://git.kernel.org/stable/c/10d9d8c3512f16cad47b2ff81ec6fc4b27d8ee10","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4a3b9e1a8e6cd1a8d427a905e159de58d38941cc","name":"https://git.kernel.org/stable/c/4a3b9e1a8e6cd1a8d427a905e159de58d38941cc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2024-46687","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-46687","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 852eee62d31abd695cd43e1b875d664ed292a8ca 51722b99f41f5e722ffa10b8f61e802a0e70b331 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 852eee62d31abd695cd43e1b875d664ed292a8ca 4a3b9e1a8e6cd1a8d427a905e159de58d38941cc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 852eee62d31abd695cd43e1b875d664ed292a8ca 10d9d8c3512f16cad47b2ff81ec6fc4b27d8ee10 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.3","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.3 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.49 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.10.8 6.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.11 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2024","cve_id":"46687","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2024-46687","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2024-09-29T15:07:56.587484Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2024-09-29T15:08:11.126Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/btrfs/bio.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"51722b99f41f5e722ffa10b8f61e802a0e70b331","status":"affected","version":"852eee62d31abd695cd43e1b875d664ed292a8ca","versionType":"git"},{"lessThan":"4a3b9e1a8e6cd1a8d427a905e159de58d38941cc","status":"affected","version":"852eee62d31abd695cd43e1b875d664ed292a8ca","versionType":"git"},{"lessThan":"10d9d8c3512f16cad47b2ff81ec6fc4b27d8ee10","status":"affected","version":"852eee62d31abd695cd43e1b875d664ed292a8ca","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/btrfs/bio.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.3"},{"lessThan":"6.3","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.49","versionType":"semver"},{"lessThanOrEqual":"6.10.*","status":"unaffected","version":"6.10.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.11","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.49","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.10.8","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.11","versionStartIncluding":"6.3","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk()\n\n[BUG]\nThere is an internal report that KASAN is reporting use-after-free, with\nthe following backtrace:\n\n  BUG: KASAN: slab-use-after-free in btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n  Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45\n  CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014\n  Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]\n  Call Trace:\n   dump_stack_lvl+0x61/0x80\n   print_address_description.constprop.0+0x5e/0x2f0\n   print_report+0x118/0x216\n   kasan_report+0x11d/0x1f0\n   btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n   process_one_work+0xce0/0x12a0\n   worker_thread+0x717/0x1250\n   kthread+0x2e3/0x3c0\n   ret_from_fork+0x2d/0x70\n   ret_from_fork_asm+0x11/0x20\n\n  Allocated by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   __kasan_slab_alloc+0x7d/0x80\n   kmem_cache_alloc_noprof+0x16e/0x3e0\n   mempool_alloc_noprof+0x12e/0x310\n   bio_alloc_bioset+0x3f0/0x7a0\n   btrfs_bio_alloc+0x2e/0x50 [btrfs]\n   submit_extent_page+0x4d1/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n  Freed by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   kasan_save_free_info+0x37/0x50\n   __kasan_slab_free+0x4b/0x60\n   kmem_cache_free+0x214/0x5d0\n   bio_free+0xed/0x180\n   end_bbio_data_read+0x1cc/0x580 [btrfs]\n   btrfs_submit_chunk+0x98d/0x1880 [btrfs]\n   btrfs_submit_bio+0x33/0x70 [btrfs]\n   submit_one_bio+0xd4/0x130 [btrfs]\n   submit_extent_page+0x3ea/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n[CAUSE]\nAlthough I cannot reproduce the error, the report itself is good enough\nto pin down the cause.\n\nThe call trace is the regular endio workqueue context, but the\nfree-by-task trace is showing that during btrfs_submit_chunk() we\nalready hit a critical error, and is calling btrfs_bio_end_io() to error\nout.  And the original endio function called bio_put() to free the whole\nbio.\n\nThis means a double freeing thus causing use-after-free, e.g.:\n\n1. Enter btrfs_submit_bio() with a read bio\n   The read bio length is 128K, crossing two 64K stripes.\n\n2. The first run of btrfs_submit_chunk()\n\n2.1 Call btrfs_map_block(), which returns 64K\n2.2 Call btrfs_split_bio()\n    Now there are two bios, one referring to the first 64K, the other\n    referring to the second 64K.\n2.3 The first half is submitted.\n\n3. The second run of btrfs_submit_chunk()\n\n3.1 Call btrfs_map_block(), which by somehow failed\n    Now we call btrfs_bio_end_io() to handle the error\n\n3.2 btrfs_bio_end_io() calls the original endio function\n    Which is end_bbio_data_read(), and it calls bio_put() for the\n    original bio.\n\n    Now the original bio is freed.\n\n4. The submitted first 64K bio finished\n   Now we call into btrfs_check_read_bio() and tries to advance the bio\n   iter.\n   But since the original bio (thus its iter) is already freed, we\n   trigger the above use-after free.\n\n   And even if the memory is not poisoned/corrupted, we will later call\n   the original endio function, causing a double freeing.\n\n[FIX]\nInstead of calling btrfs_bio_end_io(), call btrfs_orig_bbio_end_io(),\nwhich has the extra check on split bios and do the pr\n---truncated---"}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-08-04T09:31:16.672Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/51722b99f41f5e722ffa10b8f61e802a0e70b331"},{"url":"https://git.kernel.org/stable/c/4a3b9e1a8e6cd1a8d427a905e159de58d38941cc"},{"url":"https://git.kernel.org/stable/c/10d9d8c3512f16cad47b2ff81ec6fc4b27d8ee10"}],"title":"btrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2024-46687","datePublished":"2024-09-13T05:29:18.429Z","dateReserved":"2024-09-11T15:12:18.249Z","dateUpdated":"2026-08-04T09:31:16.672Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2024-09-13 06:15:13","lastModifiedDate":"2026-08-04 11:20:15","problem_types":["CWE-415","CWE-416"],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2024-09-29T15:07:56.587484Z","id":"CVE-2024-46687","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA 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fix a use-after-free when hitting errors inside btrfs_sub","CVE":"CVE-2024-46687","Year":"2024"},"notes":[{"CveYear":"2024","CveId":"46687","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk()\n\n[BUG]\nThere is an internal report that KASAN is reporting use-after-free, with\nthe following backtrace:\n\n  BUG: KASAN: slab-use-after-free in btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n  Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45\n  CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014\n  Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]\n  Call Trace:\n   dump_stack_lvl+0x61/0x80\n   print_address_description.constprop.0+0x5e/0x2f0\n   print_report+0x118/0x216\n   kasan_report+0x11d/0x1f0\n   btrfs_check_read_bio+0xa68/0xb70 [btrfs]\n   process_one_work+0xce0/0x12a0\n   worker_thread+0x717/0x1250\n   kthread+0x2e3/0x3c0\n   ret_from_fork+0x2d/0x70\n   ret_from_fork_asm+0x11/0x20\n\n  Allocated by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   __kasan_slab_alloc+0x7d/0x80\n   kmem_cache_alloc_noprof+0x16e/0x3e0\n   mempool_alloc_noprof+0x12e/0x310\n   bio_alloc_bioset+0x3f0/0x7a0\n   btrfs_bio_alloc+0x2e/0x50 [btrfs]\n   submit_extent_page+0x4d1/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n  Freed by task 20917:\n   kasan_save_stack+0x37/0x60\n   kasan_save_track+0x10/0x30\n   kasan_save_free_info+0x37/0x50\n   __kasan_slab_free+0x4b/0x60\n   kmem_cache_free+0x214/0x5d0\n   bio_free+0xed/0x180\n   end_bbio_data_read+0x1cc/0x580 [btrfs]\n   btrfs_submit_chunk+0x98d/0x1880 [btrfs]\n   btrfs_submit_bio+0x33/0x70 [btrfs]\n   submit_one_bio+0xd4/0x130 [btrfs]\n   submit_extent_page+0x3ea/0xdb0 [btrfs]\n   btrfs_do_readpage+0x8b4/0x12a0 [btrfs]\n   btrfs_readahead+0x29a/0x430 [btrfs]\n   read_pages+0x1a7/0xc60\n   page_cache_ra_unbounded+0x2ad/0x560\n   filemap_get_pages+0x629/0xa20\n   filemap_read+0x335/0xbf0\n   vfs_read+0x790/0xcb0\n   ksys_read+0xfd/0x1d0\n   do_syscall_64+0x6d/0x140\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n[CAUSE]\nAlthough I cannot reproduce the error, the report itself is good enough\nto pin down the cause.\n\nThe call trace is the regular endio workqueue context, but the\nfree-by-task trace is showing that during btrfs_submit_chunk() we\nalready hit a critical error, and is calling btrfs_bio_end_io() to error\nout.  And the original endio function called bio_put() to free the whole\nbio.\n\nThis means a double freeing thus causing use-after-free, e.g.:\n\n1. Enter btrfs_submit_bio() with a read bio\n   The read bio length is 128K, crossing two 64K stripes.\n\n2. The first run of btrfs_submit_chunk()\n\n2.1 Call btrfs_map_block(), which returns 64K\n2.2 Call btrfs_split_bio()\n    Now there are two bios, one referring to the first 64K, the other\n    referring to the second 64K.\n2.3 The first half is submitted.\n\n3. The second run of btrfs_submit_chunk()\n\n3.1 Call btrfs_map_block(), which by somehow failed\n    Now we call btrfs_bio_end_io() to handle the error\n\n3.2 btrfs_bio_end_io() calls the original endio function\n    Which is end_bbio_data_read(), and it calls bio_put() for the\n    original bio.\n\n    Now the original bio is freed.\n\n4. The submitted first 64K bio finished\n   Now we call into btrfs_check_read_bio() and tries to advance the bio\n   iter.\n   But since the original bio (thus its iter) is already freed, we\n   trigger the above use-after free.\n\n   And even if the memory is not poisoned/corrupted, we will later call\n   the original endio function, causing a double freeing.\n\n[FIX]\nInstead of calling btrfs_bio_end_io(), call btrfs_orig_bbio_end_io(),\nwhich has the extra check on split bios and do the pr\n---truncated---","Type":"Description","Title":"btrfs: fix a use-after-free when hitting errors inside btrfs_sub"}]}}}